Chapter Text
The summer of 2004 in Gwangmyeong was draped in a heat so heavy it felt like a physical weight on the shoulders of everyone living in the apartment complex. It was the kind of humidity that made the cicadas scream with a desperate, rhythmic intensity, a sound that five-year-old Seo Changbin already found himself nodding along to, his small fingers tapping out a matching beat against the plastic armrest of his stroller. Though he was technically old enough to walk, his mother often insisted on the stroller for the trek to the neighborhood park when the sun was at its zenith, fearing he might melt into the asphalt.
But today, Changbin was on his feet. He had a mission.
Standing at the edge of the sandpit, he adjusted the brim of his blue sun hat. Beside him, clutching his hand with a grip that was surprisingly firm for a four-year-old, was Kim Soojin. To the rest of the world, she was just the girl from the floor below, the daughter of his mother’s best friend. To Changbin, she was the person he had been tasked to guard. He took this responsibility with the solemnity of a knight of the round table, even if his armor was a yellow t-shirt with a faded cartoon dinosaur on the front.
"Soojin-ah, stay behind me," Changbin said, his voice carrying the self-important gravity that only a child who has recently mastered tying his own shoes can possess. "The sand is very hot today. I will check for rocks first."
Soojin nodded, her messy pigtails bouncing. She looked up at him with wide, trusting eyes—the kind of eyes that made Changbin feel ten feet tall instead of just barely three and a half. "Okay, Oppa. Be careful of the glass."
"I am always careful," he promised.
The playground was a sprawling landscape of primary colors and weathered plastic. To an adult, it was a modest collection of slides and swings nearing their expiration date. To Changbin and Soojin, it was a kingdom. The towering slide was a mountain peak that touched the clouds; the creaky bridge was a treacherous pass over a river of molten lava; and the sandpit was a vast, uncharted desert where treasures lay buried beneath the surface.
They spent the first hour in a state of focused industry. Changbin used his sturdy blue bucket to create the foundation of a fortress, while Soojin was in charge of the decorations. She had a prized possession: a bright red plastic shovel with a glittery handle that her father had bought her from the stationary store. With it, she meticulously smoothed the edges of their sand walls, her tongue poking out of the corner of her mouth in concentration.
"Look, Oppa," she whispered, pointing to a small, translucent pebble she had unearthed. "A diamond for the queen’s room."
Changbin leaned over, squinting at the rock. "It is very shiny. Put it in the middle so the dragons cannot reach it."
As they worked, the air around them seemed to vibrate with the sounds of other children. There were the shrieks of toddlers near the baby swings and the distant, rhythmic thud of a basketball being dribbled on the nearby court. For a long time, their corner of the sandpit remained an island of peace. Changbin felt a deep sense of contentment. He liked the way the sun felt on the back of his neck, and he liked the way Soojin always waited for his approval before placing a new "jewel" on their castle.
However, peace in Gwangmyeong was often a fragile thing, especially when the "big kids" decided they were bored.
The shadow fell over their fortress before they heard the footsteps. A boy, perhaps seven or eight years old, with a jagged haircut and a smirk that didn’t reach his eyes, swaggered to the edge of the pit. He was a regular at the park, known for being the kind of child who didn't know how to play without breaking something.
"That’s a stupid house," the boy said, his voice loud and unnecessarily harsh. He stood with his hands on his hips, looking down at their hard work.
Changbin froze. He felt a sudden, cold prickle of apprehension in his chest. He looked at Soojin, who had gone very still, her small hand tightening around the handle of her red shovel.
"It is not a house," Changbin said, standing up and brushing the sand from his knees. He tried to make his voice sound steady, like his father’s voice when he was talking to a difficult neighbor. "It is a fortress. And we are busy."
The older boy laughed, a sharp, unpleasant sound. "It looks like a pile of dirt. I bet it breaks easy."
He stepped into the sandpit, his heavy sneakers landing dangerously close to the western wall of their castle. Soojin let out a small, soft gasp and pulled her feet back.
"Don’t," Changbin warned, stepping forward so he was positioned between Soojin and the intruder. "Go play on the swings. This is our spot."
"I don’t want to go to the swings," the boy sneered. He looked past Changbin, his eyes landing on the glittery red shovel in Soojin’s hand. "I like that shovel. Give it to me."
Soojin pulled the shovel closer to her chest, her knuckles turning white. "No. It’s mine. My Appa gave it to me."
"I don't care," the boy said, reaching out. "Give it here, or I'll kick your dirt house into the grass."
The atmosphere in the sandpit shifted instantly. The heat seemed to intensify, the buzzing of the cicadas sounding like a warning siren in Changbin’s ears. He looked at the older boy—who was a full head taller and significantly broader—and then he looked back at Soojin. Her lower lip had begun to tremble, a telltale sign that tears were only seconds away.
Something shifted inside Changbin. It wasn't a thought, exactly, but a visceral reaction. It was the same feeling he got when he heard a heavy bass line in a song—a steady, unyielding thrum of purpose. He realized that if he didn't do something, Soojin would lose her shovel, her castle, and her smile.
"She said no," Changbin said. He didn't just say it; he growled it. He planted his feet in the sand, his small hands curling into fists at his sides. "Leave her alone."
The older boy blinked, clearly not expecting resistance from a five-year-old. "What did you say, brat?"
"I said leave her alone!" Changbin shouted, the volume of his own voice surprising him.
The bully’s face turned a mottled red. He reached out and shoved Changbin’s shoulder, hard. Changbin stumbled back, his sneakers sliding in the loose sand, but he didn't fall. He righted himself immediately, the fear that had been lingering in his stomach replaced by a white-hot flash of indignation.
"You’re a mean giant!" Soojin cried out from behind him, her voice high and wavering.
The boy ignored her, stepping closer to Changbin, his hand raised as if to shove him again. But Changbin didn't wait. He lunged forward, not with a punch, but with a clumsy, full-body tackle, throwing all his weight against the older boy’s midsection.
They both went down into the sand in a tangle of limbs. Changbin wasn't strong enough to hurt the boy, but he was fast and relentless, fueled by a primal need to protect. He scrambled over the older boy’s legs, shouting for his mother, his voice a clarion call that echoed across the playground.
"Eomma! Eomma!"
The older boy, panicked by the sudden physical confrontation and the loud summons of an adult, scrambled to his feet. He pushed Changbin away one last time—sending him sprawling onto his back—and took off running toward the apartment entrance, muttering threats that neither of the children understood.
The sandpit was quiet again, save for the sound of Changbin’s heavy breathing and the distant calls of their mothers, who were now hurrying across the grass.
Changbin sat up, spitting a bit of sand out of his mouth. His yellow dinosaur shirt was ruined, covered in grit and sweat, and he had a stinging scrape on his elbow. He looked over at Soojin. She was still sitting in the same spot, her red shovel clutched so tightly to her chest that it looked like a part of her body.
"Soojin-ah," he panted, crawling over to her. "Are you okay? Did he touch the shovel?"
Soojin looked at him, her eyes wide and wet. A single tear escaped, carving a clean path through the dust on her cheek. She didn't answer at first. She just stared at him, as if she were seeing him for the first time. Then, she let out a long, shaky breath and reached out, touching the scrape on his elbow with one tiny finger.
"Oppa is bleeding," she whispered, her voice full of awe and heartbreak.
Changbin looked at his elbow. A few small beads of red were blooming against his skin. It stung, but it was a "cool" kind of sting—the kind of injury you got when you did something important. He puffed out his chest and wiped his face with the back of his hand, probably just smearing more sand into his eyes.
"It is nothing," he said, trying to mimic the stoic expression of the heroes in his cartoons. "I told you I would check for rocks. I caught the biggest rock of all."
Soojin didn't laugh, but the trembling in her lip stopped. She leaned forward and suddenly threw her arms around his neck, burying her face in his shoulder. She smelled like sunblock and the orange juice she had for breakfast.
"Oppa is a hero," she sobbed into his shirt. "You fought the giant."
Changbin wrapped his arms around her, patting her back clumsily. He felt a strange, new sensation—a warmth that had nothing to do with the Gwangmyeong sun. It was the feeling of being needed. It was the realization that his presence meant safety for her. At five years old, he didn't have the vocabulary for "devotion" or "vocation," but the seed was planted. He would be her shield. He would be the one who stayed when everyone else ran.
Their mothers arrived seconds later, a whirlwind of concerned voices and wet wipes.
"Changbin-ah! What happened to your shirt? And your arm!" his mother cried, pulling him up and inspecting the scrape with an expert eye.
"A big boy was mean to Soojin," Changbin explained, pointing in the direction the bully had fled. "I had to push him away."
Soojin’s mother picked her up, wiping the tears from her face. "Is that true, Soojin-ah? Did Changbin protect you?"
Soojin nodded vigorously, her pigtails whipping back and forth. She pointed to the red shovel, which was now safely tucked under her mother’s arm. "He wanted my shovel. But Changbin-oppa said no. He was like a lion, Eomma! A big, yellow lion!"
The mothers exchanged a look—a mixture of relief and amusement. They spent the next ten minutes cleaning up the children and their gear, though the sand castle was beyond saving, having been mostly flattened during the scuffle.
"Come on," Changbin’s mother said, taking his hand. "Let’s go home and put a bandage on that 'hero' wound. And then maybe we can have some cold watermelon."
The walk back to the apartment building was slower than usual. Changbin felt the exhaustion of the afternoon catching up to his small legs, but he refused to be carried. He walked beside Soojin, their fingers interlaced.
As they reached the entrance to the elevators, Soojin stopped and looked up at him. The sun was beginning to set, casting long, golden shadows across the lobby. She looked at the colorful bandage on his elbow—one with little stars on it that his mother had pulled from her purse.
"Oppa?"
"Yeah?"
"Will you always fight the giants?" she asked.
Changbin looked at her. He thought about the older boy’s smirk and the way his own heart had pounded in his ears. He thought about the weight of her hand in his. He didn't hesitate.
"I will always fight them, Soojin-ah," he promised. "As long as you are with me, I will never let them take your shovel."
Soojin smiled then, a bright, gap-toothed expression that made the scrape on his arm stop stinging entirely. "Okay. Then I will always bring the jewels for our house."
They rode the elevator up in silence, the soft chime of the floors marking the end of their first great battle. When the doors opened on the fourth floor, Soojin’s mother led her out.
"See you tomorrow, Hero-oppa!" Soojin called out, waving her hand until the elevator doors slid shut.
Changbin waved back, a small, tired smile on his face. As the elevator continued up to the sixth floor, he looked at his reflection in the mirrored doors. He didn't see a small boy in a ruined dinosaur shirt. He saw a protector.
He didn't know then that the giants would eventually stop being children on a playground. He didn't know that the world outside of Gwangmyeong was full of men with beautiful faces and hollow souls—men who wouldn't just want a red shovel, but would want to steal the very light from her eyes. He didn't know that one day, he would be miles away, trapped behind the walls of a training center, while she faced a giant he couldn't see.
But for now, as he stepped out onto his own floor and followed his mother into their apartment, he felt invincible. He had made a promise. And in the world of Seo Changbin, a promise was the strongest thing there was.