Chapter Text
The limousine was moving at the slowest possible speed as requested by their young master, making the drive relaxed and pleasant, yet Senku’s heart was frantic as if they were in a race. His lips twitched—dry and cracked, searching for something wet to replenish both his skin and his desires. He thirsted for the plush lips millimeters away from his own, belonging to a man who smelled and looked so good that no one would be able to resist.
Not even a man who left no room for emotional desire.
Their hot breaths were louder than the car’s engine, with their racing hearts a close second. The young master trapped Senku in the corner of the leather seat—nowhere to go, nowhere to hide—as he stared down at the scientist’s trembling mouth.
This was far from the universal university experience Senku had envisioned. He had expected a few rational distractions from his scientific pursuits, but certainly nothing like… this.
The previous semester had started quite differently.
“And what do constellations actually consist of?” The professor asked, surveying the lecture hall. The room was quiet since this was a refresher lesson from their preschool that was a decade ago and would only be elaborated from someone who held great memory and understanding.
“Apparent groupings of stars bound by perspective rather than proximity,” Senku said smoothly. Before he could elaborate, another voice cut in, practically vibrant with confidence.
“Precisely as Senku said, even though they are visually linked from our vantage point, those celestial bodies are often light-years apart in actual depth!”
Senku glanced toward the far left, observing the handsome face bridging the exact continuation he had been about to speak.
For some reason, Senku wanted to one-up him. “Though if you calculate their proper motion over a ten-thousand-year vector, those static asterisms warp entirely due to stellar drift.”
“And that apparent shift relies heavily on their precise parallax and radial velocity!” Ryusui chimed in without missing a beat, grinning brightly.
“Great job, Senku and Ryusui. Very impressive and in depth as expected from my top students. For the others, I’ll help you keep up,” the professor commended, prompting a soft ripple of approving nods throughout the room. “Now, let’s turn to page twenty-eight, where we’ll examine the Andromeda constellation…”
It was a scene that played out almost every single day ever since Senku had become classmates with Ryusui, the charismatic heir to a multi-billion-dollar maritime empire. Although Senku consistently held the top rank in their entire batch with Ryusui coming in second, it was Ryusui who reaped the lion's share of recognition—a high-profile figure holding the key to almost anyone’s bright future.
And the brains matched the beauty too much, and unconsciously or not, it lingered in Senku’s mind, unable to forget the corporate heir no different from the others.
“Senku! I heard you can create anything?” Ryusui had asked, sliding into the seat right beside him. The surrounding students exchanged nervous glances, since only Taiju or Yuzuriha ever dared to sit next to the prodigal scientist.
Senku, however, did not seem bothered. It was about time to interact with the man who could possibly understand his scientific rhetorics best.
Their exchanges only ever happened during shared classes where they dominated recitations, constantly bouncing complex concepts off each other like they possessed clairvoyance, always knowing what’s to be said and what came next. A fragrant smell wrapped him, as if caressing him to the heir's way.
But Senku kept his eyes on the sky outside, watching the afternoon sun hide behind a thick layer of clouds. “You’re finally recruiting me to your company?”
“Depends,” Ryusui said, leaning in closer. “If the rumors are true, I’d want you for myself.”
Senku turned to meet his gaze, though his eyes mindlessly strayed to the captain’s smooth, moisturized lips before catching himself. So this was how he looked up close—much prettier than he was afar on his actual chair. “Oh? In what sense?”
Ryusui replied, “I can supply whatever my family's conglomerate needs. I am more interested in eyeing you for my personal fulfillment.”
Senku tried to steer his thoughts toward the obvious answer—the ambitious heir wanted to leverage his mind for passion projects. Ryusui was notorious for utilizing talented people to fuel his vast desires.
Yet, Senku's brain strayed into an undiscovered territory, contemplating what was said in a different light,
An entirely different kind of fulfillment.
“You want to use my lip balm? I have plenty!” Ryusui flashed a bright, blinding smile, catching the scientist off guard.
Senku broke his eyes away with a sharp sigh and stuck a pinky in his ear. “You’re a billionaire. You could easily gather anyone’s personal information if you wanted to.”
Before Ryusui could answer, their physics professor stepped into the room, cutting the conversation short.
The next afternoon, Senku walked into his laboratory on the first floor of the university's right wing. The familiar, sterile bite of concentrated isopropyl alcohol hung in the air, but it was soon overtaken by a warm, smoky vanilla scent, the exact perfume of the man who had sat beside him the day prior.
Footsteps echoed softly through the quiet, breaking the monotonous hum of the magnetic stirrer. Ryusui roamed around, scanning the room with his wondrous curiosity. After sixty-seven seconds, he came to a stop right at Senku’s side, finally observing the only man in the room.
Senku glanced at him from head to toe. The corporate heir was dressed in full lab attire, wearing even more protective gear than the scientist himself, which drew a small chuckle from him.
“Finally made you smile,” Ryusui beamed.
“Was my face that bad yesterday?” Senku smiled.
Ryusui placed both hands on his hip. “Could be better. I wanted to see more on your face besides that usual smug grin.”
Senku hummed, thinking if he should say what he thought. After a few, he replied, “I bet you’ll invoke more when you actually try.”
“Yeah,” Ryusui stepped closer, his voice dropping slightly. “I’ll keep on trying.”
Senku swallowed hard, quickly turning his focus back to the glass beakers on his desk. “You have an entire staff at your disposal. Why are you surveilling my work yourself?”
Ryusui laughed. “Where is the fun in chasing a treasure through the eyes and hands of others? I have the resources, so I will do it myself.”
“You’ll get tired of it. These rigid chemical formulas are boring to a businessman, even if they mean the world to the creator.”
“This one,” Ryusui said, pointing directly at a clear liquid in a flask by the distance, “Is the exact resin coating used on my ship's hulls. It provides maximum corrosion resistance against harsh saltwater environments. And the alcohol, I assume you’re testing something related to shrinking fluids?”
Senku’s eyes widened for a fraction of a second before his face split into a wide, genuine grin.
“Not bad.”
Finally, a man standing on his exact same footing.
He had always known Ryusui was sharp from their academic debates, but he had not expected him to possess such practical chemical intuition.
“Not Bad? I deserve better than that after all my attempts to keep up with a brilliant mind like you,” Ryusui said, giving a sweet smile.
“If you want more praise, then get to work.”
Over the next two months, a strict routine during school days took shape. Senku would occupy the lab two hours before the campus closed, and like clockwork, the golden head would be there, hovering around to assist. Eventually, Ryusui spent so much time in the room that he no longer needed Senku’s instructions to know what to clean, mix, or prep. After each session, they would part ways without unnecessary small talk.
The rest of the university's science club quickly learned to leave the lab entirely to the two of them during those two hours. The sheer density of their intellect created an overwhelming pressure that no one else could match.
Yet, the chemistry between them was no longer confined to glass tubes and heat burners.
Senku often found himself practically dressed by the captain the moment they stepped inside. Ryusui would gently slide the white lab coat over Senku's shoulders, pull the nitrile gloves over his fingers, and adjust his safety goggles. Only after ensuring Senku was fully equipped would Ryusui dress himself.
Their skin brushed frequently in the narrow aisles. Their shoulders bumped whenever they leaned in over a workstation. When an experiment required absolute precision, Ryusui would rest his chin lightly on Senku’s shoulder, watching the scientist’s steady fingers drop solutions into a tiny volumetric pipette. Before leaving, Ryusui made a point to master the disinfection and shutdown procedures just so Senku could rest, then taking time to carefully scan Senku’s body from head to toe to make sure no hazardous chemicals had spilled on his clothing before going home.
On one warm afternoon, Senku’s task involved repeatedly pouring liquids between a series of heavy beakers. Ryusui stood nearby, watching with sharp, curious eyes, clearly wanting to attempt the procedure himself.
Before Ryusui could move, Senku spoke without turning around. “Your hands are untrained for this.”
Ryusui crossed his arms. “You’ll never know unless you let me try.”
Senku sneered. “You know how steady my hands are, unlike yours.”
“I don’t, actually,” Ryusui murmured, closing the small distance between them until he stood directly behind Senku. A bluff—Ryusui was a sharp observer that in a few more weeks he’d become Senku himself, so there was no way he'd not see how his hands were as focused as his head.
“Is that a challenge?” Senku scoffed regardless. “Even if the ground beneath us cracked open, my hands wouldn't shake a millimeter.”
Five cool fingertips suddenly brushed against the bare skin of Senku's nape. Ryusui’s fingers slowly traced the line of his spine, sliding down toward his waist, sending an involuntary shiver through his frame even though his lab gown shielded him from the captain’s skin.
Senku's breath hitched instantly, hands growing cold, and the beaker in his grip gave a tiny, visible tremble.
Ryusui leaned in close, his mouth hovering right by the scientist's ear. “Where are those steady hands now?”
“…It’s a completely normal neurological reaction to a sudden stimulus,” Senku muttered, forcing his hands to steadily pour the liquid into a smaller vessel.
Ryusui’s hot breath fanned against Senku's ear, turning the shell of it bright red, before he drew his hand back to his side. “You’d stand unmovable through an earthquake, but you break down over a tiny tickle? You have faced defeat, my friend!”
Senku felt a surge of heat rush through his veins, pooling heavily in his stomach and lower body.
“How about you try it then and see how difficult it could get,” Senku said, spinning around abruptly. He tilted his chin up to catch Ryusui’s gaze, which held a raw, dark intensity he hadn't seen before, then the pressure made his eyes fall on his chin. He shoved the two heavy glass beakers into the captain’s hands.
Ryusui let out a confident, arrogant smirk, ready to tackle what seemed like the simplest task of the week. He raised the larger beaker, tilting it toward the smaller one.
Before a single drop of white liquid could spill out, Senku’s right hand shot forward. His gloved fingers pressed firmly against the sides of Ryusui’s neck, shoving him backward until the captain’s back hit the plain white wall with a dull thud. Senku’s hand then slid down, landing flat and firm against the center of Ryusui’s warm collarbones.
“Pour, Goldilocks.” Senku demanded, his voice low and sharp, his index and middle fingers taking their time making their way to Ryusui’s strong, firm chest that even their thick uniform couldn’t hide.
Ryusui’s gaze locked onto Senku’s, unable to look away from the fierce challenge gleaming in the scientist's red eyes.
“See?” Senku smirked.
He reached out to reclaim the glass beakers, but before he could pull back, Ryusui locked his fingers tightly between Senku’s, trapping their hands together around the cold glasses. In one swift, fluid motion, Ryusui drove his right shin between Senku’s legs and pivoted his weight, using the leverage to flip their positions and slam Senku back-first against the wall.
“Pour, darling,” Ryusui demanded back, his sharp grin flashing his canines.
Senku’s smug composure instantly shattered. A heavy wave of more heat flooded his senses, beads of sweat breaking out at his temples as he struggled to maintain his signature confident smile even if it twitched.
Locked in an intense staring match he couldn't bring himself to break, Senku felt his fingers tremble beneath the combined heat of his heavy lab gloves and Ryusui’s burning grip.
Senku prayed that Ryusui won’t look down, for he somehow found Ryusui’s rigid hands that are much bigger enveloping his own as… pleasant.
“You’re not looking at the beakers. What an irresponsible scientist you are,” Ryusui whispered after catching Senku’s unyielding eyes, his voice deep and raspy against the scientist’s cheek, causing his lower lip to go completely dry. “I am not your dangerous experiment, you see.”
A sudden, reckless impulse flared in Senku’s mind, a quiet temptation stirring between his slightly trembling legs that defied every bit of his logical training.
“Maybe you’re an experiment I’m willing to explore,” the words tumbled out of his mouth before his brain could filter them. The space between them froze in silence.
Ryusui’s smirk instantly vanished. Senku’s heart plummeted straight into his stomach.
Cold, suffocating regret instantly washed over Senku's mind, realizing he had crossed a line he couldn't step backwards from.
As the captain’s grip slowly loosened, Senku violently yanked his hands free, clutching the beakers to his chest as he walked away.
That marked the final interaction they ever had in that laboratory before summer arrived.
No matter how Senku tinkered with his rocket prototypes, his mind kept wandering back to those large hands gripping his own. He wondered what more could have happened if his gloves had not been in the way, and whether his pants would feel far more restricted if it were skin to skin.
And why Ryusui, of all people?
When a problem was left unsolved, all it took was an experiment to experience the anomaly directly. Yet even if Senku wanted to run the test, he could not simply force Ryusui into it. A human being is not a stable chemical that could be easily toyed with, mixed, and poured into test tubes to observe a reaction.
More importantly, they had not parted on good terms. Things had drifted into silence a month ago. Only a week remained before they would see each other in school again, and Senku had no clean formula to return them to baseline.
Especially when he felt he had crossed a line. Meeting Ryusui's playful, light tickle with a sudden, reactive choke seemed like a reckless mistake, one that could have easily been avoided if Senku had not let his eyes wander to the defined column of Ryusui's throat. His gaze lingered too long on the sharp, prominent curve of his Adam's apple, a striking line that shifted so fluidly whenever Ryusui spoke or swallowed, highlighting the taut, elegance of his neck.
A wire inside the prototype’s microchip hissed and burnt. As the scientist reached for it mid-thought, a sharp, exposed edge pricked his skin, drawing a fast bead of blood from a deep wound. Senku sighed. If that man were here, he would have insisted on keeping him protected. He would have offered his assistance, and he would have...
Perhaps he would have kissed the pain away.
“Oh, really now,” Senku laughed defeatedly, dragging a palm down his face. He found it difficult to believe he was entertaining thoughts so overtly vulgar. “This is logical decay, not exhilarating at all. What am I even thinking?”
The doorbell chimed through the house. Being alone, he was forced to abandon his workspace and answer it. When he pulled the door open, he was met with a refined, slender figure of an ambiguous beauty. Dressed in flawless formal attire, their golden locks were styled in tight, immaculate waves, carrying quiet efficiency.
“Greetings, Sir Ishigami. I am Francois, the Nanami estate’s butler,” Francois bowed smoothly, resting a gloved hand over their chest. Senku was hardly surprised by them finding his house and the presence of a butler—the Nanami conglomerate was one of the multi-billionaire families in the country.
Seeking him out directly, however, was startling. “What brings you here?”
“Master Sai has received an opportunity to pursue higher studies at India’s premier university, his long-cherished dream school,” Francois began.
Senku cut in, “Yeah, Sai is a monster in all our mathematics subjects, but he lags behind in applied sciences. I’m guessing you want me to tutor him?”
“A sharp mind indeed, Sir Ishigami,” Francois smiled subtly. “I trust that master has chosen you for good reason.”
Senku felt his cheeks warm slightly. Though Francois had not specified which of their masters had requested him, the source was glaringly obvious. His shoulders relaxed a fraction. Perhaps this was the bridge needed to reset their connection.
Or, if it failed, Senku was certain he would adapt quickly. He had learned to operate in solitude long ago while his father was away, and his head was too far into the stars for anyone to hold his attention on the ground.
Senku was so absorbed in his calculations that he barely noticed Francois pulling out a sterile cotton swab, a small bottle of topical antiseptic, and a bandage. “May I assist with your injury? I keep first-aid supplies readily available, as Master Ryusui frequently acquires splinters and minor cuts while crafting his ship models.”
Senku offered his hand to Francois, who began treating the cut with practiced precision. He asked, “He still builds prototypes, too?”
“He has crafted hundreds of ship models entirely by hand. After a few years, those blueprints are brought to life on a grand scale by his team of marine engineers,” Francois explained, securing the bandage neatly over the wound.
Senku exhaled at the reminder about the possibility of a dead tie with an awesome shipwright, missing his chance to watch Ryusui build what he loved, just as the heir had once watched Senku turn his lab into a personal playground. The thought created a faint heaviness in his chest, so he snapped his focus back to the business at hand. “What schedule does he prefer?”
“Master is free this entire week, so you may come at your earliest convenience.”
“Alright. Let’s go now.”
Francois had already been advised that Senku did not operate like an ordinary person. His schedule could pivot from rigid structure to pure spontaneity in an instant, and he required no heavy textbooks or physical reference materials—only his mind. Francois showed no surprise at his immediate departure.
Upon arrival, Senku paid little mind to the opulence of the Nanami estate, far more focused on the prospect of diving into pure scientific instruction.
The grand hallways were a display of unbridled luxury, lined with expansive marble flooring that reflected the soft glow of crystal chandeliers above, framed by rich mahogany paneling and adorned with rare, gilded antiques. Yet neither the gold leaf accents nor the priceless porcelain vases caught his eye. All his attention was drawn to the large, framed photographs and painted portraits lining the walls. Ryusui and Sai appeared in numerous shots together across both formal galas and candid moments, with Francois present in the background of a select few.
There were no other people other than the three of them.
“This is Master Sai’s room,” Francois announced, knocking gently on the heavy door. Upon receiving a muffled call from within, Francois opened it.
The room was dominated by an expansive workstation featuring nine high-resolution monitors. Even from a distance, Senku recognized a custom-built rig engineered for heavy compilation and algorithmic processing. Beside the keyboard lay multiple professional graphics tablets and styluses, and tall bookshelves crammed with advanced mathematics texts on the corner, organized cables running along the floor, and a minimalist bed tucked into the corner, entirely dwarfed that it could remove the “bed” from bedroom.
“Master, this is Sir Senku Ishigami. He has graciously offered his time to assist you immediately,” Francois introduced. Sai slumped his shoulders, visibly shrinking under Senku’s intense presence. The scientist's crimson eyes and naturally unreadable face could easily be taken as intimidating, to say nothing of an intellect that regularly makes his peers sweat and professors sweatier.
Senku caught the tension instantly and let his gaze soften. “What branches of science are we covering first?”
“E-everything that was taught from the foundational years up to the present. If... that’s alright,” Sai stammered, standing up nervously in an oversized t-shirt and loose pants. His attire was the only relaxed thing about him, while everything practically radiated the opposite.
“Simple enough,” Senku said, folding his arms with a faint smile. “Just listen closely and speak up when you hit a wall.”
Once Francois quietly closed the door behind them and went out, the two settled at a clear wooden desk where Sai handled his administrative work, from academic modules to initial game concepts. Sai arranged his notebook and pen, still visibly tense in the presence of the young scientist. Senku kept a comfortable distance, breaking down fundamental biological concepts with a cool, structured clarity.
As the hours slipped by, Sai’s anxiety began to dissolve. He was surprised to find that Senku was remarkably attuned to subtle shifts in body language, creating an environment where asking questions or making missteps carried no disgrace. Sai never felt looked down upon, even when he struggled to process a complex sequence.
While waiting for Sai to finish jotting down a set of notes, Senku remarked, “I take it you were spending most of your hours programming games and letting formal coursework sit on the back burner?”
Sai winced, letting out a self-conscious laugh. “You figured that out... though I suppose my setup gives it away. And yes, I was deep into developing a new game set in the medieval era when this offer came out of nowhere. The entrance examination is next week!”
“Given the concepts you've retained today, you’ll clear it easily. Your entire skill set revolves around high-level logic and problem-solving. The exam is just another system to decode.”
Sai flushed, rubbing the back of his neck. “I-it’s nothing extraordinary. Anyone could manage it with enough effort.”
Senku offered a quiet chuckle, amused by the sheer contrast between the two brothers.
“I only wish your brother shared your affinity for quiet,” Senku muttered, digging an ear with his pinky finger.
“Y-you get used to the noise after a while,” Sai offered a soft smile. “Though if you explicitly tell him to tone it down, he actually listens. He made sure to keep his distance after that period where I refused to speak with him.”
Now that Senku considered it, Ryusui could be surprisingly compliant when pushed correctly. He told him to find out if he could create anything. He did. He challenged him to figure if his hands were truly steady. He did.
He felt a sudden, curious urge to see just how far that compliance extended.
“...Let’s move to the next module,” Senku said, refocusing his mind.
They pushed through the remainder of the curriculum, translating raw chemical equations and physical laws into structured lessons until the sun dipped below the horizon, giving way to the cool light of the moon.
“I’ll return tomorrow. What time works best for you?” Senku asked, checking the hour.
“Any time is fine, but...” Sai paused, scratching his head. “If we could meet late in the afternoon and run into the evening, that would be ideal. Though if morning is better for you, I can just rely on an energy drink.”
“No need for that,” Senku rested his hands on his hips. “I’ll arrive at four in the afternoon so you can keep your morning sleep.”
“T-thank you. Truly.”
Stepping out into the grand hallway, Senku caught a figure standing near the entrance in his peripheral vision. He looked up to find Ryusui holding a paper grocery bag under his left arm, likely stocked with snacks for Sai’s late-night coding sessions.
Ryusui was wearing a crisp white compression shirt that clung tightly to the broad expanse of his chest and the sharp contours of his shoulders, outlining the athletic build of a seasoned sailor. The fabric yielded to every movement of his muscular torso, a sight that Senku’s eyes registered with an unbidden, subtle spike of heat.
“Look at the dutiful brother,” Senku smirked, showing no outward sign of being caught off guard, but his eyes remained feasting. “Francois could have easily carried those up.”
Senku let out a quiet breath as Ryusui offered a warm, familiar smile. The heir replied, “He’s prone to skipping meals after long sessions of heavy study. I hope he wasn't too much of a handful.”
“He handles instruction well,” Senku crossed his arms. “And he likes me.”
“As he should,” Ryusui placed his free hand on his hip, his stance oozing effortless confidence. “I like you, too.”
Senku’s expression flattened for a split second before he countered, “If that were true, you wouldn't have gone radio silent all summer.”
“I didn't have your number.”
Senku extended his hand. Without hesitation, Ryusui pulled out his phone and passed it over. Senku opened the dialer app, and before he could finish entering the third digit, his own contact profile populated the screen.
Senku’s lips curved into a wide, triumphant grin. “Liar.”
Of course it was there. He was dealing with a corporate heir who possessed the resources to secure any personal line in the city within minutes if he truly desired it. He himself reminded Ryusui of this power.
Ryusui let out a low laugh, a smooth, rich sound. Senku felt as though he were observing a delicate chemical reaction—one that required his undivided attention to ensure it didn't boil over. “Is the number correct?”
“If you had bothered to place a call, you would already have your answer,” Senku said, handing the device back. “The last bus route leaves shortly. I’m heading out.”
He brushed past Ryusui, making his way down the corridor.
“A private car is waiting for you at the main entrance,” Ryusui called out, remaining where he stood without turning around. “And your compensation has already been transferred.”
Senku paused, drawing his phone from his pocket to check his banking app.
He turned back to face Ryusui’s back. “This figure is enough to fund five high-grade rocket prototypes.”
“Then let us aim for twenty tomorrow, shall we?”
“If that's the scale you're aiming for...” Senku bit his lower lip, cutting off the rest of his thought before it could slip out. “Nevermind.”
“Make it thirty, on the condition that you tell me what’s currently crossing your mind,” Ryusui finally turned, his sharp gaze fixing onto Senku, who promptly avoided direct eye contact.
The scientist stuck a pinky in his ear, chuckling. “You’ll stop talking to me again.”
“I have no intention of repeating that mistake,” Ryusui’s tone shifted into something firm and resolute. “You have my word.”
“Even with a verbal guarantee, basic behavioral science dictates that promises don't inherently prevent a breach of contract,” Senku shrugged, turning on his heel, leaving Ryusui alone to decode everything himself.
Upon returning to his quiet house, Senku prepared for the night.
Just as he settled in, his phone vibrated against the nightstand. A faint smile touched his lips almost instantly. He picked up and accepted the call. “Goldilocks.”
“Have you arrived home safely?”
Ryusui’s voice came through the receiver lowered and smooth, carrying a velvety, intimate resonance that seemed to vibrate directly against Senku's ear. He placed the speaker directly on his right ear.
“Yeah.”
“Great!”
Senku sat back against his headboard. “I assume you called with something meaningful to say.”
“As captain, it is my duty to check on my crew, and that principle extends to those I hold close. You’re my friend after all.”
Friend. The term felt laughably insufficient.
“Is that what we’re calling it now?” Senku countered smoothly, a faint hum vibrating in his chest. “I don’t recall letting my friends trace their fingers along my neck in the lab.”
On the other end, Ryusui let out a low, breathy laugh that sent a tremor straight to Senku’s core. “A fair point. A friend wouldn’t strangle my neck either.”
“A text would have served the same purpose,” Senku replied.
“So you can leave me on delivered to ignore the question I posed earlier?”
Senku gave a short laugh, his feet slightly swaying where they rested above the bed. “Back to this again? Oh great captain, let it drop.”
Ryusui let out a rumbling chuckle over the line before pressing further. “What if I withhold tomorrow’s payment?”
Senku was unconditionally driven purely by the urge to share knowledge and see another mind grasp the elegance of science, and payment is unnecessary.
But giving that logical answer would yield a remarkably boring result.
“Then I’d have no incentive to share what was on my mind,” Senku replied smoothly. “A payment so huge like that makes me far more inclined to work more for you than what I’m asked for.”
Silence stretched across the line. Senku felt surprisingly steady, letting Ryusui take the lead in dragging the truth into the light. The scientist leaned his head back against the headboard, a sly smirk tugging at his mouth as he listened to the steady rhythm of Ryusui’s breathing.
In a voice that dropped an octave, rich with quiet intent, Ryusui asked, “...And what exactly would you do?”
Senku felt a sudden, sharp pulse of heat center low in his gut, a flush creeping beneath his skin. He looked at his free hand, feeling the phantom touch of the man who once enveloped his hand, then he looked down to see something curved beneath his pajamas.
“...I’m tired,” Senku murmured, ending the call.
He tossed the phone onto the mattress and lay back against the firm bed. The urge to slip a hand beneath his waistband was intensely tempting, but he recognized the feedback loop for what it was. Succumbing to the impulse would only reinforce the neural pathway, wiring his brain to seek that immediate hit of dopamine again and again, and that would be dangerous.
He closed his eyes and forced his body into rest.
The following morning, Senku woke with a lingering restlessness. He had slept heavily, yet the physical tension had not dissipated with the morning light.
At ten minutes to four, Francois and a chauffeur arrived to fetch him. They reached Sai’s quarters shortly after, but repeated knocks on the door yielded no response.
“My apologies, Sir Ishigami. This is an oversight on my part,” Francois said softly, inclining their head. “Master Sai appears to have worked through the night. I did not intend to cause you inconvenience.”
A huge difference to his brother, who always operated on time. Though, Senku felt strangely relieved.
“In that case, I might as well disturb the other brother,” Senku said.
Francois escorted him down a separate wing of the estate to Ryusui’s private quarters. To his surprise, Francois opened the unlocked door and let Senku in without even knocking.
Upon entering, Senku was met with an incredible display of maritime craft, both wood and metal. The room was expansive, full of blues and creams, lined with custom display cases housing dozens of meticulously built model ships. Sunlight streamed through tall windows, illuminating the polished wood hull of a massive galleon resting on a central display table, surrounded by fine drafting tools, rolled blueprints, and tiny brass fixtures.
Unlike his brother’s, the room was more of a bedroom than a workspace, with an art gallery of ships on the side.
Senku stepped closer, staring in absolute awe at the sheer scale of the collection, his mind wanting to write an analysis on each single piece.
“If the scale models carry this level of structural precision, the actual vessels must be a sight to behold!” Senku remarked, his eyes tracing the intricate rigging, the alignment of the starboard framing, the sweep of the hull, and the impossibly detailed miniature figures of Ryusui, Sai, and Francois stationed on some of the decks. The engineering feat thrilled him, striking a chord remarkably close to the rush he felt when designing rocketry.
“You need only say the word, and I will take you to the shipyards,” After a door closes, Ryusui’s voice came from nearby, accompanied by a quiet laugh. “We can even bring your rocket prototypes along to compare aerodynamic principles against any hydrodynamic design of your choice.”
Senku looked behind him, his chest locking as his eyes met the view. Ryusui stood there draped in nothing but a single towel, leaving a breathtaking spread of golden skin entirely exposed. The scientist’s mind went blank, his breath stuck somewhere in his throat while his eyes trailed aimlessly, seduced by the subtle sheen on Ryusui's skin. Droplets of water caught the light, slipping slow and heavy down the arch of his collarbone, tracing the line of his chest, and drawing Senku’s helpless gaze deeper down.
“Now that sounds like an experiment worth running,” Senku said, his eyes stuck on Ryusui’s dip above his hips, thanking himself for not forgetting the captain’s words to respond to.
“Dressing now would be a waste of time considering that Sai will wake up soon,” Ryusui placed his hands on his hips above the towel to let the scientist get the full view of everything uncovered. “Let’s talk.”
Senku closed his eyes to compose himself, then he went back to the ships. “What drives you to push these builds to this level of detail?”
“Greed,” Ryusui answered simply.
Senku finally shifted his gaze to meet his eyes that held nothing but burning passion.
Ryusui continued, his excitement spilling out. “My desire stems from outright ambition—my intense drive to pull an idea from the mind and force it into my hands. I envisioned myself navigating ships that belonged entirely to me, so I built a hundred of them. When I set my sights on something, I exert every effort until it is mine.”
Senku offered a slight smile, captivated despite himself by the resilience and clarity of Ryusui's drive. It was an attractive nature that was uncompromising, operating on an internal logic that was as absolute as any physical law.
“So,” Ryusui stepped closer, his voice dropping slightly. “Everybody has greed in them, and you’re one of them.”
Senku felt a sudden cool prickle over his skin. He knew where it was heading. “Greed is not a part of my character.”
Ryusui said softly, “Your eyes say otherwise.”
He passed by a window, and the sunkissed build of the captain came closer. “What is it that you desire?”
He had anticipated that Ryusui would keep his distance, continuing their unspoken game of subtle provocations. But direct deception was useless against someone as perceptive as the captain. And true to his word, once the man locked onto a target, he would let the greed of knowing answers take over.
So, Senku kept his mouth shut.
Ryusui took another step forward. “Whenever you look my way, your eyes wander everywhere except my face. There is something you're hiding, something you're keeping locked away.”
Senku took involuntary steps back until the edge of a mahogany display cabinet met his spine.
“I gave you my word that I wouldn't pull away again,” Ryusui murmured, closing the remaining space until he was standing directly over him. “So tell me—what do you want from me?”
Helplessness creeped in the scientist. “Cornering your subject isn't going to give you answers.”
“Then I’ll stay right here,” Ryusui said smoothly, holding his ground, his presence heavy and warm. “For as long as it takes to get an answer.”
Senku let out a sharp breath. The pulse of the confrontation hit him like a sudden spark, turning his blood hot and sending a sudden, involuntary smile to his lips. He stayed silent, testing the boundary. Ryusui leaned in further, trapping him cleanly against the cabinet.
Ryusui’s gaze swept over his expression. He reached up, his large, warm fingers gently catching Senku’s chin, tilting his head slightly upward. “You've never been the quiet type, Senku. Do you enjoy forcing me to pursue you?”
“That's an unverified hypothesis and definitely not for me to figure out,” Senku rasped out, his palm coming up to rest lightly against the broad, firm plane of Ryusui’s chest. He could feel the quickness of the heart beneath the fabric—a rapid, heavy pulse that betrayed the captain's cool composure. A sly smirk tugged at the corner of Senku's mouth. “Though if you're so eager to collect the data, you're free to keep trying.”
“Maybe I’m asking the wrong question. I’ll rephrase,” Ryusui stated, his mouth reaching the ear of the shivering man below him. “What do you want me to do to you?”
Senku demanded, “Hold my hands. Like you did back in the lab.”
Ryusui’s smile curved into something fiercely, beautifully intense. Slowly, his fingers bled down from Senku’s chin, tracing the warm column of his neck before sliding down to lace tightly into Senku’s palm, swallowing his smaller hand whole. He did the same to the other hand. Without the barrier of gloves, the raw contact hit him harder. Ryusui applied a slow, deliberate pressure, his thumbs stroking the fragile pulse point at Senku’s wrists—a rhythm that set off a quiet wildfire in his nerves, stealing the air right out of his lungs.
The captain spotted his injured finger and placed a delicate kiss over the bandaid.
A crisp knock sounded against the wooden door frame.
Senku caught his breath, his pulse banging against his ribs. “I have a student waiting. Let go.”
Ryusui’s grip did not slip, his broad fingers remaining firmly intertwined with Senku's, his thumbs continuing its slow, deliberate pressure against his warm palms. “Tell me what else you want first.”
Senku let out a breathless, dry laugh, trying to anchor himself back to pure logic. “Science takes priority. Let me go handle your brother.”
“Is this not a field of science as well?” Ryusui challenged softly, his chest hovering mere inches from the startled scientist, his scent of sea salt and cedar that he used in his shower completely filling Senku's senses.
Matching Ryusui's pace was a heavy strain on his focus, leaving Senku struggling for a brief second to formulate a proper response. “We'll resolve this later before I get driven home.”
“During,” Ryusui corrected firmly, his eyes dark with unyielding intent. “I am driving you home myself.”
“Fine.”
Ryusui finally relaxed his grip, his hand lingering for a fraction of a second before sliding away entirely. They exchanged a brief, weighted glance before Senku turned toward the door, his heart still beating a rapid, chaotic rhythm.
Realizing something, Senku froze in slight panic. He whirled back toward Ryusui, who had already begun unwrapping the towel from his waist.
Slamming his eyes shut, Senku huffed irritably, "At least wait for the door to close before stripping down, you ape."
"You seemed pretty set on not turning around," Ryusui laughed, deliberately stalling his undressing with a smirk. "Or are you planning to skip tutoring Sai altogether?"
"I need a jacket. The bigger, the better," Senku demanded, his face burning while his body remained as stiff as stone.
Ryusui turned his head, thick brows knitting in confusion before he suddenly caught sight of Senku's predicament down there. He snapped his head away, kept his towel secured, then pivoted toward his wardrobe with his entire frame trembling.
Senku's blood boiled at the subtle vibration of the captain's shoulders, his face twisted and ugly. "Stop laughing, damn it!"
Ryusui broke. A loud, booming laugh echoed through the room, his whole body shaking as he searched through the racks. He choked out between breathless wheezes, "W-what's your favorite color?"
"Irrelevant. Completely irrational question. Just hurry up!"
Ryusui returned, still snickering softly, carrying an oversized white and red zip-up hoodie from their school's varsity tennis team.
Senku immediately cursed his decision to wear light grey sweatpants and a thin shirt today, swearing to stick strictly to dark, heavy fabrics in the future.
Ryusui carefully draped the hoodie over Senku's shoulders, avoiding any direct contact with bare skin to keep from escalating the situation further. "I've never seen anyone react quite like this from a simple hold of hands."
"Just ignore it," Senku muttered, fixing his gaze stubbornly on the window frame to avoid Ryusui's eyes. "I don't know why it's happening. I don't have the data."
"Yet," Ryusui added, gently smoothing out the wrinkles on the shoulders before taking a step back. "I'll help you figure it out."
Senku was extremely distressed not only by embarrassment, but the lack of facts and figures regarding this phenomenon. The fatigue from his sleepless night was catching up to him, making him increasingly irritable, and he was overwhelmed by the temptation to deal with his erection. Overstimulated and distracted, he had no idea which problem to address first, and it all translated to his hysterical breathing.
Ryusui snapped his fingers to pull him back to reality. “What does r=1−sin(θ) look like when it's plotted in a 360-degree circle?”
Senku's brain automatically kicked into gear. The numbers and spatial vectors mapped out in his mind, calculating the geometric curve defined by the equation. It took him thirty seconds—far longer than usual to the noise in his head—before he arrived at the solution.
"It looks like a peach," Senku answered.
Ryusui laughed softly, his eyes bright with amusement though he clearly attempted to hold it back. "It's a heart, but close enough. Does it still hurt?"
Senku hadn't fully regained his footing yet. "What?"
"Down there," Ryusui clarified gently. "How do you feel? Your temperature rose quickly earlier."
Senku analyzed his own physical state. The arousal was still present, but the intense spike had plateaued. The panic had evaporated the moment Ryusui forced his logic back. His shoulders dropped, the tension leaving his muscles—he was successfully grounded.
"I owe you one," Senku said, scratching the back of his neck. "At least I have protocol next time."
Ryusui's eyes gleamed playfully. "So there’s a next time?"
Before Senku's face could catch fire again, Ryusui flipped Senku and placed a hand between his shoulder blades to steer him toward the exit. "We're not letting this calm state go to waste! Off you go!"
"Good. Your face is making me sick," Senku shot back, letting himself be pushed forward.
As soon as they stepped past the doorway, Ryusui extended his arms to circle Senku’s front, sending Senku's heart rate spiking all over again as he felt warm breath brush against his ear. Ryusui reached for the zipper, pulling the oversized hoodie up to Senku's neck, hiding his thighs. "Can't have Sai catching on."
Even after the hoodie was secured, Ryusui kept his arms loosely looped around Senku's waist. Senku remained still, allowing the proximity, instinctively sensing that the captain was processing his own thoughts with…this matter.
"Agh!"
Senku delivered a sharp elbow back into Ryusui's ribs the second he caught a shadow turning the corner of the hallway.
"What? Are you hard again—?" Ryusui teased under his breath.
"Shut—!" Senku kicked Ryusui's half-bare leg back into the bedroom. "Francois! Is Sai ready?"
Francois showed up then bowed with immaculate composure. "Yes, Sir Ishigami. Master Sai is awake and awaits you in his study. He sends his deepest apologies for the delay."
Ryusui peeked out from the doorframe, offering a smooth smile. "Don't worry about it, Francois. I had a few urgent matters to clear up with him anyway. Give Sai my regards."
“Yeah, very important,” Senku said, rolling his eyes. “Lead me the way, Francois. I’d love to do science,” he eyed Ryusui, “…science that actually matters.”
"They say to save the best for last, and that science for later is just as important," Ryusui shrugged from inside his room, his smug expression entirely hidden from the butler's view. "We'll resume our discussion later."
Francois turned and began leading the way down the long corridor. Before stepping forward, Senku swiftly raised a middle finger over his shoulder at Ryusui before picking up his pace. Ryusui's booming laughter echoed down the marble hallway, giving Senku roughly twenty-one seconds to regain his composure, drain the color from his face, and suppress his physical reaction.
—
Inside the study, Sai and Senku resumed their positions from the previous day. They moved through complex theories at a breakneck pace, with Sai grasping advanced principles far faster than before. Reference sheets, scribbled calculations, and graphite shavings scattered across the wide desk, filling the room with the distinct scent of paper and freshly sharpened pencils.
While Sai was engrossed in deriving an equation, Senku caught sight of the small bandage on his own index finger. His heart gave an unbidden flutter at the sudden thought of Ryusui pressing his lips against the bare wound. Would it feel any different was the question.
"I think this wraps up everything," Sai said softly, bringing Senku back to the room.
Senku fixed his throat, hiding his fingers through his fist. "Exemplary work. You absorbed that ridiculously fast—it took a total of nine hours to run through a full structural review. As expected, your processing is top-tier."
Sai's cheeks flushed as he let out a self-conscious laugh. "I was hoping to finish early so you could rest."
Senku blinked. "What?"
"Y-you look completely exhausted..." Sai rubbed his neck. "And I thought we could get dinner before you leave. It's the least we can do to thank you."
“Science is significant and should be passed down to everyone. No sweat,” Senku smiled faintly. "Though I wouldn't say no to one of those canned energy drinks."
Sai beamed. "I'll grab one for both of us!"
Senku felt a surge of interest—this was an ideal window to gather intel on how to make Ryusui wrapped in his finger.
Not wanting to be heartless and immediately interrogating him about his brother, Senku started by asking about Sai himself. He learned how Sai had distanced himself from the Nanami conglomerate in search of quiet, hoping to build an independent life abroad. As the cold caffeine kicked in, Sai gradually unraveled his usual anxiety, offering quiet chuckles and maintaining direct eye contact far more frequently.
As the conversation shifted toward his past, Sai's expression darkened. "If you don't mind me asking... have people ever tried to exploit your intellect for their own gain?"
Senku's playful demeanor receded quietly, recognizing the underlying weight of the question—in the Nanami household, Sai had been treated as little more than a valuable asset to secure corporate leverage. Ryusui had likely faced a variation of that same pressure.
"My circumstances were entirely different. I wasn't born to be a successor of anything let alone a corporate slave, and I've always had the leverage to reject anyone attempting to manipulate my work. I was raised to hold my ground on what I want to achieve." Senku took a slow sip from his can, monitoring Sai's tense posture.
"Though," Senku added quietly, "it can get quiet up at the top."
"I can only imagine how isolating that must feel," Sai replied, leaning forward slightly. "At least I had Ryusui. Overwhelming as he is, having someone who understands that weight makes a difference."
Senku's pulse quickened slightly.
Having an absolute equal to stand alongside sounded like an intriguing factor.
Senku shrugged his shoulders. "I'll manage. As long as I can keep doing science so my ass can reach the moon, being all alone is a non-issue."
Sai's gaze softened with a trace of quiet sadness towards his way, and the scientist wasn’t sure why.
Yet he continued, “I know you’ll succeed in India. You’ll get to be a person who’s skills and knowledge are tied in your own hands, and yours alone.”
A sudden tear spilled over Sai's lashes.
"Whoa, easy there," Senku immediately wheeled his chair closer. He reached out to pat Sai's trembling shoulder, but the moment his palm made contact, Sai flinched violently. Senku retracted his hand instantly, recalling that physical touch only heightened the sobbing man's anxiety. He shifted strictly to verbal reassurance. "Let it out. You've been holding onto that pressure for years."
They spent the next few minutes navigating the burdens of high intellect and complicated family dynamics, with Senku guiding the conversation until Sai's breathing stabilized. They then went about the struggles of being abroad, with the scientist sharing his old man who had to work far from home. Sai laid his heart about leaving Japan between sniffs.
"Despite everything, I'm going to miss them, especially my brother," Sai admitted softly, wiping his eyes. "I have a strong feeling I'll pass the entrance exams. Ryusui put in immense effort to bridge the gap between us and make sure I felt supported. Walking away sounds wrong, but feels right."
Ryusui's ability to read people wasn't just a tool for business negotiations—he had refined it out of a desperate need to reconnect with his brother, making sense of how he could see through the eyes of the scientist.
Senku held back the dozen specific questions he wanted to ask about the captain. Instead, he offered a faint smirk. "If Goldilocks puts you down, just give the word and I'll put him down myself."
Sai let out a genuine laugh. "He's not a threat anymore. He really is a good person."
Senku’s face fell flat, his eyes forming a thin line. "Huh. Is that so?"
Sai flinched as Senku's face shifted terrifyingly fast. "W-what did he do to you...?"
The knock on the door signalled dinnertime.
The conversation yielded far more questions than answers, but whatever Senku wanted to know about Ryusui, he decided he would simply ask the young master himself. They stood, and Senku led the way toward the door.
Before they stepped out, Sai asked, “Are you sure you don’t want to borrow some of my clothes instead? They’re much closer to your size.”
Senku would like that—baggy clothes were inefficient, restricted movement, and dragged on the floor—but he was wearing a jacket twice his size for a reason he wouldn't reveal even after death.
He forced a smile, a sweat trickling his temple. “...I like this jacket just fine.”
They headed downstairs for dinner, where Ryusui was already engaged in conversation with Francois. Senku deliberately kept his eyes averted from the young master, wary that another look might trigger a reaction.
As they approached the table, Sai caught the hem of Senku’s hoodie, bringing him to a sudden halt. He kept his eyes fixed firmly on the floor, his curly hair curtaining his face as if he needed the barrier just to speak. “Uhm… thank you for everything. I’ll carry everything you taught and said with me.”
Knowing that direct eye contact would only intimidate Sai, Senku kept his gaze forward and offered a low hum of appreciation. Sai released his grip, while Ryusui watched the exchange in quiet silence.
The grand dining room had high ceilings, intricate gold leaf molding, and a sparkling crystal chandelier illuminated a massive polished mahogany table. The feast laid out before them was an extravagant display of culinary wealth, featuring delicate slates of fresh sashimi, steaming bowls of rich ramen, and slow-simmered Japanese curry.
Sai took his seat opposite Ryusui, while Francois gestured for Senku to take the chair directly adjacent to the young master.
"Did my brother give you any trouble?" Ryusui asked due to his observation of them earlier, taking a sip of his drink—only to choke.
Senku had already finished his entire plate. In under two minutes flat.
Before Ryusui could voice his shock, Senku wiped his mouth with a napkin. "Food is strictly fuel to keep the engine running. And for the record, I was the one troubling Sai."
"N-no!" Sai interjected quickly, nearly dropping his chicken katsu. "I was the issue!"
The two brothers launched into a lively back-and-forth exchange about the day's events. Sai kept the emotional details to a minimum out of embarrassment, opting instead to passionately explain the scientific concepts he had mastered and the game architecture he was designing.
Senku watched the dynamic unfold with quiet interest. He saw how Ryusui's face lit up with genuine warmth as he listened to his brother, far more open than the confident mask he usually wore around others.
Suddenly, beneath the drape of the heavy tablecloth, a warm, broad hand slid over Senku's thigh and firmly enveloped his hand. Senku closed his eyes and heavily breathed to compose himself, his free hand propping by the table to hold his chin to hide as if there’s nothing going on underneath the table.
Despite Senku’s attempts to hide it through his relaxed composure and with Ryusui’s active conversation with him, Sai was just as a genius as both of them. If he doesn’t put piece and piece together, he’ll at least sense it.
Especially when Ryusui kept on complimenting the scientist and kept looking in his way with the most sincere eyes he had seen.
“I have a lot of backlogs to handle since I woke up late. I’ll be heading out first,” Sai said, standing up from his chair. He glanced at Senku with eyes that the scientist couldn’t fully decipher, though they were unquestionably brimmed with quiet gratitude. He bowed his head slightly. “Thank you again.”
Once Sai and Francois had left the study, Ryusui’s gaze followed the closed door for a moment. Under the table, his hand gave Senku’s a firm, reassuring squeeze. “He really does like you.”
“Got a problem with that?” Senku asked, a sly smirk tugging at his mouth.
“No issues at all. I didn’t know he was easily capable of making a genuine friend in only two meetings,” Ryusui smiled softly, his posture relaxing. “That takes a massive weight off my shoulders for when he goes abroad. It’s good to know he’ll be alright.”
Senku grimaced. “Now I feel like a complete jerk for assuming you were about to get jealous.”
The captain chuckled. “Who says I’m not?”
“Well, it looks to me like you’re willing to give just about anything to your brother.”
Ryusui turned to him, his gaze suddenly focused. “I am not that generous.”
Senku’s mouth popped open, his eyebrows soaring up toward his static-defying hair. But before he could formulate a comeback, Francois stepped back inside to announce that the vehicle was ready. Senku clicked his tongue—the captain had gotten absurdly lucky escaping further interrogation.
Stepping past the grand estate doors, Senku blinked at the lengthened silhouette waiting in the driveway. “I thought you were driving me home yourself.”
“They operate on my command. Technically, I am,” Ryusui smiled, guiding Senku toward the spacious back cabin of the luxury limousine.
Francois instructed the chauffeur, “Please drive with extreme care and slow speed, as per the young master’s explicit request.”
After Francois extended their farewells over the lowered window, Ryusui immediately reached over to draw the thick privacy curtain, completely isolating them from the driver upfront. Senku swallowed hard, the sudden enclosure shrinking his world down to the two of them—right back to the stifling heat that had been building between them all day.
Two months of unspoken tension in the lab, a summer of silence, and hours of calculated tutoring had all converged into this single, enclosed space. The variables were finally set.
Ryusui shifted across the leather seats, closing the distance until he was sitting right beside the scientist. “Science time,” the captain teased, his tone smooth and low, causing Senku to snort despite the sudden jump in his heart rate.
Ryusui always seemed to hold the upper hand, the one that drove racing hearts and reactions, and Senku decided it was time to rebalance the equation.
Senku’s posture went upright, his signature stance when presenting or proposing a study. “I want to conduct an experiment on myself to gather data regarding physical and sexual stimuli.”
As expected, the boldness stunned Ryusui into momentary silence. The captain focused his full, undivided attention on him, his expression sharpening into the exact same intense gaze he had worn when Senku slipped up during their previous encounter in the lab.
“It’s a field of study I am fundamentally unfamiliar with, and you happen to be the variable triggering these physiological reactions,” Senku continued, keeping his voice strictly analytical. “I don’t understand the mechanics behind it yet, which is precisely why I intend to run a trial. However, I recognize that you're a human subject with your own autonomy, not an inert chemical compound, so this can't be treated like a routine laboratory test.”
Senku carefully monitored the visual feedback—a flush creeping up Ryusui’s cheeks and coloring the tips of his ears, paired with a gaze that felt intense yet entirely devoid of pressure.
He pressed on, “If you're willing to act as the test subject, excellent. If not, I’ll simply find someone else to—”
“I caused this,” Ryusui cut in sharply, a clear edge of irritation tinting his voice. “How do you expect to gather valid data by introducing an entirely different variable?”
“Maybe someone else can make me hard. Who knows until I test it?”
Ryusui leaned forward abruptly, crowding into Senku’s space and effectively pinning the scientist against the corner of the plush leather seat. Internally, Senku’s mind reeled into a mild panic, a light sheen of cold sweat breaking out across his skin. His heart pumped violently, feeling as though it might burst straight into Ryusui’s mouth—which was now dangerously close, plump, and occupying his entire vision.
“If you're looking for clean results, shouldn't you thoroughly examine the primary source first?” Ryusui smirked. The top buttons of his white buttoned shirt were undone, offering a subtle glimpse of his collarbones and firm chest, while the prominent rise of his Adam’s apple bobbed with his heavy breathing—just as tense beneath the surface as Senku was.
Senku refused to back down, broadening his own smirk to match. “Ah, so this is that famous greed surfacing, huh?”
Through the narrow glass tint of the moonroof above, streetlights flickered in rhythmic passes across Ryusui’s face—illuminating a man whose vast resources could command fleets, yet who currently sat waiting on a mere scientist’s word,
And the man who will redirect his entire future.
Senku’s eyes dropped to Ryusui’s lips. A surging confidence rushed his body after the captain gave him all the green lights to have power since yesterday, reaching out and resting his fingertips beneath Ryusui’s chin.
“I require absolute compliance with my instructions. That is my only condition,” Senku demanded.
“Wish granted,” Ryusui replied instantly, without a moment’s hesitation.
Senku chuckled dryly. “No chance it’s that simple. Define your conditions. Time constraints, boundaries, personal comfort levels—lay out the full framework.”
“Subject to my professional availability,” Ryusui murmured, leaning in another fraction of an inch. “And if my schedule is full, I will make the time.”
“...That’s the extent of your conditions?”
Ryusui, with his signature arrogant grin, nodded once.
What the absolute hell.
Even basic chemical reactions and experimentation operated within strict limits. Yet Ryusui—a living, breathing human being with boundless pride—was handing total authority over to him without a single reservation. Any rational mind would draw back from such absurdity, suspecting something was fundamentally broken in the man on top…
But Senku loved that there was something wrong with him.
A heavy surge of heat pooled low in Senku's gut, killing whatever remaining instinct he had to retreat. He looked up, meeting the dark, unblinking intensity of Ryusui's brown eyes.
“Unbelievable,” Senku muttered, a sudden, quiet warmth spreading across his chest as his mind mapped out the endless, wild possibilities of this unconstrained run.
“Then let us test it,” Ryusui whispered, gently cupping Senku’s flushed cheek. “What is your first command?”
Senku’s gaze darted from Ryusui’s lips to his eyes, then back down to his lips. Taking the silence as consent, Ryusui began to close the final inch between them.
Panic flared. Senku shoved Ryusui backward with a sudden burst of physical strength he didn't even realize he possessed—especially in his sleep-deprived state. Ryusui stumbled back slightly, his expression shifting to immediate concern as his fingers caught Senku’s visibly trembling wrist.
Senku couldn't decipher which emotion stemmed from the sensory overload. He was shaking uncontrollably, a wave of intense heat radiating through his body as his eyes darted erratically around the cabin.
Recognizing the onset of an acute anxiety response like when the scientist asked for a jacket, Ryusui reached toward the vehicle’s console to retrieve a medical kit, but Senku reached out and grabbed him firmly by the collar, dragging him back into place.
“G-give me a minute,” Senku rasped out between heavy, shuddering breaths.
“We can do it another time—”
“Did I order to stop?”
Ryusui’s eyes widened slightly before a faint, fond smile touched his lips. He remained right where he was, gently tracing the line of Senku’s warm cheekbone with his thumb, carefully tracking his respiratory patterns and fighting for his place in the scientist’s cluttered mind with his touch.
As a captain, Ryusui was trained to analyze all conditions possible out at the worst and adapt instantly. He knew that if a simple touch or a laced grip could overstimulate Senku's threshold to this extent, he needed to approach every move with absolute patience and delicate precision, acting as a steady anchor rather than an overwhelming force, starting with his hands.
“Teach me,” Senku demanded, his breathing slowly stabilizing into a manageable rhythm.
Ryusui shifted his hand from Senku's cheek down to his chest, applying a calm, grounding pressure over his heart. “Rule number one: focus on releasing physical tension. Guarding against the sensation only restricts your nerve responses and causes discomfort.”
The captain brought his thumb up, lightly pressing against Senku’s bottom lip to part his mouth. “Keep your breath steady. And tilt your head slightly to clear my nose.”
Senku’s eyebrow raised. “That’s it?”
“Experience will teach you more than words I say,” Ryusui whispered. “Follow my pace. If it becomes too much, push me away again.”
Senku took one final, grounding breath before pulling Ryusui in by his collar.
Ryusui closed his eyes, resting his lips gently against Senku’s until he felt the scientist’s mouth soften beneath his. Slowly, deliberately, he angled his head, catching Senku’s lower lip between his own. He pressed forward with a light, rhythmic pressure, pulling back slightly before adjusting the angle, keeping the movement slow, fluid, and entirely unhurried. Feeling Senku’s knuckles white-knuckling his collar, Ryusui stroked the back of his hand, silently reminding him to loosen his grip—and Senku complied, his tense shoulders dropping.
After ten seconds of passive reception, Senku began to shift his head, his lips tentatively moving against Ryusui’s as he tried to decipher the rhythm.
“Breathe,” Ryusui murmured against his skin between soft presses.
Senku drew a sharp, audible breath through his nose and continued. He struggled with the mechanics—uncertain of how much pressure to exert, when to shift angles, or how to keep their noses from colliding in the tight space.
A click distracted them both.
“Watch the teeth,” Ryusui whispered, his voice laced with low amusement. “Or is biting part of your experiment?”
“Shut up and keep still,” Senku groaned against his mouth, turning his face crimson as he adjusted his angle.
Senku hated how pathetic it felt to take direction when he was supposed to be running the experiment, forced to rely on heavy, ragged breaths just to keep from being consumed by Ryusui.
Yet, as his brain decoded the spatial timing, Senku finally matched Ryusui’s cadence, smoothing out the initial friction.
“You’re…really good,” Ryusui rasped, his voice dropping into a low, gravelly hum. Senku’s eyes fluttered open just enough to catch the dark, blown-out look in Ryusui’s gaze, only to close them off from the intensity. The words sounded so sweet it made his toes curl under his rubbershoes.
Senku reached up to cup Ryusui’s face, taking in the heat of his smooth skin, the dark resonance of his voice, and the soft, wet sounds of their mouths meeting—a sensory overload that made his sweatpants feel agonizingly tight.
A sudden tremor ran through Senku’s frame, prompting Ryusui to ease back to check on him, but Senku immediately tightened his grip on the captain's face, dragging him back in. For the first time, Ryusui let out a heavy, shuddering exhale of his own because of this display of obsession, shattering his composure and coaxing a muffled, stifled sound from deep within Senku’s throat—a soft, involuntary whimper he couldn't choke back.
The pace escalated instantly. Senku drove the kiss forward with hungry impatience, and Ryusui responded in kind, their mouths sliding together as quiet slick sounds filled the quiet cabin, exchanging heat and saliva in an increasingly messy, desperate rhythm. The captain’s free hand travelled around Senku’s smooth neck, jaw, and cheek, struggling to be gentle.
Feeling the sharp tension locking up Senku’s jaw, Ryusui whispered against his lips, “Stop holding it in.”
“You too,” Senku managed to murmur, his fingers tangling tightly into the hair at the nape of Ryusui's neck as he pulled him impossibly closer. “Or are you afraid the driver might hear what happens when I finally undo you?”
Ryusui’s breath hitched, a low, dangerous groan escaping his chest before he let out a short, breathy laugh against Senku's mouth—which the scientist greedily kissed away.
Ryusui parted his lips further, slipping his tongue forward to lightly trace the seam of Senku’s lips before pulling back entirely—despite the man below him using his remaining strength to keep him close. Senku’s fingers clung to Ryusui’s collar, his knuckles rigid with desperate leverage, but the captain gently disentangled his grip, leaving Senku stranded in the sudden, cold air.
He hovered over the scientist, monitoring the data before him—crimson eyes that were usually so sharp and calculated now trembled and dazed, a body shaking with overstimulation, and a deep, burning flush spreading from his neck all the way to the tips of his ears. Encased in his thick varsity hoodie, Senku was practically an oven.
Ryusui considered removing the heavy garment to help him cool down, but he hesitated, unsure if touching him further would push his nervous system over the edge. Instead, he forced a pause.
“W-why did you stop...” Senku panted, his eyes half-lidded as he tried to focus through the haze.
As much as Ryusui hated seeing anyone in distress, the sight of the brilliant scientist entirely unravelled by his touch sparked a thrill in his chest. He remembered his own promise back in the lab—to evoke something deeper, something real on the face of the man who always seemed entirely out of reach. Wish granted—and all it had taken was the tip of his tongue.
He lightly shook his thoughts away.
“Your core temperature jumped way too high, way too fast,” Ryusui noted, his voice quiet.
Senku stared up at him, taking in the raw, unfamiliar intensity in the captain's gaze and face.
“Impressive monitoring,” Senku rasped out, wiping his wet lower lip with the back of his thumb as his chest heaved. “Didn't realize you were a thermometer.”
“A sudden thermal spike like that is hazardous, especially given your susceptibility to panic responses.”
“I’m the scientist here,” Senku huffed with a weak chuckle. “Leave the diagnostic analysis to me.”
Ryusui held his gaze in silence. It was the same non-pressuring look as before, but now heavy with an unspoken, overwhelming weight. Feeling thoroughly exposed under that piercing gaze, Senku snapped his head to the side, pressing his burning cheek into the leather upholstery to escape the eyes that felt as though they were trying to consume him whole.
Once his breathing stabilized after two minutes of quiet, Senku broke the silence. “What about you?”
“Hm?”
“You said you were seeking personal fulfillment from me.”
Ryusui swiped the left side of his hair behind his ear. “I am still compiling my observations.”
Senku chuckled. “Copycat.”
The limousine smoothly decelerated to a halt outside Senku’s residence. Ryusui extended a hand, supporting Senku as he slowly sat up to ensure his blood pressure didn't drop too quickly. With practiced care, Ryusui smoothed down Senku’s messy bangs, used his thumb to dab away the sweat and stray moisture near his lips, and straightened the crumpled collar of his hoodie, waiting patiently while the scientist attempted to regain his composure.
Reaching across, Ryusui slid the privacy curtain open, alerting the chauffeur while keeping a steadying hand clamped over Senku’s arm to brace his trembling legs. The automatic door glided open. The moment Senku’s feet hit the pavement outside, Ryusui released his hold.
“I’ll see you at school,” Ryusui offered, a brilliant, confident smile breaking across his face.
Senku stared at his pretty face for several long seconds, then turned on his heel and walked toward his gate without uttering a single word.
His hands were a complete disaster.
They shook so violently that he dropped his house keys three separate times on the porch, taking an agonizing full minute just to line up the lock and step inside.
The moment the front door clicked shut, Senku’s hand plunged down into his sweatpants. He shoved his underwear aside, abandoning all restraint as the physical urge finally overwhelmed his mental control that he didn't find the time to remove his pants.
The execution was crude and unrefined. Having only tested the biological mechanism once out of idle curiosity as a child, he relied entirely on basic textbook instruction—stroking up and down with hasty, unpracticed friction. Leaning his full weight back against the hard wood of the front door, his breath came in ragged, messy gasps.
There was only one thing in his mind—do not ever think about Ryusui. Even when he gripped on to the cloth and scent of that very man.
He shouldn’t think about the sheer breadth of Ryusui’s arms, or how the hard, golden contour of his chest looked as if it had been sculpted by classical hands. He shouldn’t think about the captain’s scent—an intoxicating mix of fresh sea air and deep cedar—that clung stubbornly to the oversized hoodie that was currently filling his senses, killing all rationality. Least of all should he linger on those soft, yielding lips he had pressed against, the wet strings that tied his mouth to his—the very catalyst that had thrown his entire nervous system into absolute chaos.
He shouldn’t remember the unmasked heat in Ryusui’s eyes as he hovered over him, or the exquisite realization that the arrogant, multi-billionaire heir had been brought to a flush solely because of him.
“You’re…really good.”
And yet, as the relentless rhythm broke through his last thread of control, a sharp, broken moan fractured the quiet air. Senku called out Ryusui’s name into the empty darkness, letting the silent spaces of his living room bear witness to the man who had permanently rewritten his understanding of pleasure.
Senku looked down at his trembling hand, slick and covered in white, warm fluid. As the immediate, intrusive thought surfaced—wondering how Ryusui would do with it—he let out a dry, defeated laugh into the night.
This reaction was far beyond his ability to contain or control. He was playing entirely above, and ultimately within Ryusui’s grasp, and he could see himself begging for more.
“Fuck.”