Chapter Text
The purpose of this story is for non-profit entertainment purposes only.
All Episode characters belong to Author Yusei Matsui (2012), publishers Shueisha's: Weekly Shonen Jump, and Anime producers Funimation (2015)
Also, this story will have spoilers from chapter one, so make sure you've read the manga or seen the entire anime before reading this.
Update: 06/10/2025 - due to someone reporting this for copyright I have to edit the transcripts to only include a max 10 mins of dialogue so for the next two months or so the transcripts will be re uploaded in edited form. In the meantime you can read a copy of the full story on my tumblr. It’s my username.
Prologue: also known as Don't Skip the Prologue!
***
The Old Campus of Kunugigaoka Junior High sits on top of the mountain, with a clear blue sky making the woods seem greener.
Karma Akabane was relaxing on the stone steps, reclining back as he stretched. "Hmm, well this definitely beats being the main circus attraction." He smiled slyly before he let out a yawn.
It was quiet up here, one of the small perks, you could hear the birds and crickets. It was actually really relaxing—
A huge blast of air knocked Karma off the steps as a purple portal opened up 30 feet above him.
"What the!" Karma shouted, rolling down the steps. He winced when he hit the ground, his clothes soiled from the dirt, and a few bruises on his cheek.
Then a burnt up looking egg-shaped spaceship actually came out of the portal.
Alright, that was definitely one of the strangest things he'd seen this week.
Karma's eye widened briefly but then narrowed. "So much for quiet." He sighed and rubbed his head.
The spaceship landed on the grass, creating a wave of wind that blew his hair out of place.
Karma got to his feet and hid his butterfly knife behind his back; unlike the others, he didn't shy away from real blood.
The hatch of the ship was lifted by a grey slender arm. The pilot crouched like a predator before they jumped up in the air—Karma's eyes narrowed—and landed on the ground with well-practised precision.
Karma smiled with gritted teeth, "If you're looking for the octopus, he took off that way." He pointed his knife over his shoulder. "But, if you wanna play, I'm game."
The figure rose, making it easier for him to see.
"It is a lot more complicated than that, I'm afraid," the voice was sweeter and gentler than he'd expected.
He frowned and took a step closer.
The pilot was a woman, not human, but sort of like an android with a human face. She was tall, around 5'7 probably, and was wearing a worn-out green tactical jumpsuit that exposed her metal arms and legs.
Her face, though, was that of a young Japanese girl with bright pink hair tied up in pigtails, kind of a contrast but...
Then she smiled at him. "We don't have much time, Karma-kun!"
(What the hell!?)
He stiffened. "How did you—?"
Her smile vanished when the weird pink bracelet on her wrist beeped. "I only have 3 minutes," she said sternly. "And, the entire future depends on me getting this right," her voice rose, curling her hands into fists. "Now, where is the rest of Class E?"
Karma blinked, lost for words for a second before he shook his head. "Hold on, who are you supposed to be anyway!?"
(If she's part of the Ministry of Defence then they'd really improved their budget.)
The robot froze, confused. "Don't you recognise my face?" her voice wavered.
Karma jerked his knife at her. "Does it look like I have any idea?"
"But, it's me, Ritsu!" Her composer slipped. "I'm from the future—oh, no. No, no, no!" She hastily started poking the bracelet on her wrist, turning on an orange hologram. "Am I too early!?"
Karma's brow furrowed, lowering his arm a fraction when he saw how worked up she was getting.
(Just who the hell was this girl?)
He looked up when the purple portal above made a grumbling noise and closed in on itself.
Ritsu From the Future looked up in horror. "Oh, crap!" It kind of looked like she was sweating. "Where are they?!" she rushed over to him. "Please, Karma-kun!" She looked close to tears.
Karma's face scrunched up. "They're at Assembly, geez!" He raised his hands.
She sucked in a gob of air. "We don't have much time, come on!"
"Hey, wait for a second!"
She flung him up in the air and into her spaceship like a basketball. "Come on!"
Karma hit the soft mat of the inside of the ship and groaned.
Ritsu jumped in after him and closed the hatch as she landed in the comfy looking pilots chair and started pressing lots of buttons on the console.
Karma shakily got to his feet, clutching his bruised head. "Bitch," he hissed, shaking his head, trying to regain his bearings.
He looked around the ship, it was bare, minus the front area which had a single pilot's seat and the tinted front window.
"Hold onto something," Ritsu ordered as she pushed some kind of gearstick next to her.
"Huh?" Karma looked over at her.
Then, suddenly the ship shifted quickly, knocking him off his feet.
***
Nagisa smiled in amusement, holding his handwritten copy of the Student Council newsletter.
"Oh, we got handouts, please continue, sir!" Isogai spoke up, polite as usual.
Student council member, Araki, looked flustered. "What? N-no way. How?" he yelled before he glared at the rest of the students. "Hey, now, who killed our fun!?" said without thinking. "Uh, ahem, I mean..." He cleared his throat quickly. "Let us continue—"
But, he never got the chance when an egg-shaped spaceship burst through and knocked the two wide assembly doors off their hinges.
"It's a bomb!" one student shrieked.
Nagisa's jaw dropped as he and the rest of the students ran for cover, and Koro-sensei's disguise slipped off when he moved forward to protect them.
"Ahhh!"
The students were yelling and screaming and Araki dived off the stage in fright.
The ship never hit them though. It hovered in the air and then slowly lowered to the floor as the students gave it more than enough room.
"Everybody back away!" Karasuma yelled, moving in front of Koro-sensei who was shielding the rest of Class E with his large bulk.
"Is that guy yellow?!" a girl from the crowd yelled.
Nagisa winced.
(Oh, crap.)
The ship hit the ground with a thud that echoed.
The whole assembly was silent.
Then the hatch of the craft opened and suddenly a woman—wait, no, was that a robot?!—jumped out of the craft.
"Identify yourself," Karasuma ordered, tenser than they had ever seen him before.
"Oh, no, please! No one panic!" The pink hair woman (wait she looked kind of young). "I'm not here to hurt anyone!" She raised her arms peacefully.
"Likely story!" Professor Bitch withdrew a gun: a real one.
(So much for keeping this a secret.)
Karasuma was livid. "Don't escalate the situation?"
"I'M PROTECTING MY STUDENTS!" she shouted back.
(Oh God...)
"Oh, man..." Karma emerged from the craft rubbing his head. "That was rough."
"Karma-kun!" Nagisa yelled.
"Karma-kun, what are you doing in there?!" Koro-sensei scolded, waving his tentacles frantically.
Karma looked over at them and waved. "Oh, hey, guys."
"Okay, let's all just calm down!" the woman/girl tried to placate, as the thing on her wrist beeped. "I'm from the future and—"
The bracelet on her wrist, let out an ear-piercing beep.
"Ahhh!" The students covered their ears in pain.
The robot woman winced. "Oh...crap."
A bright light exploded from her bracelet, nearly blinding them all.
Nagisa shut his eyes quickly and felt a strange vibration ripple across the room and temporarily block out all the sound.
The lights exploded above them, spraying shards of glass.
Some of the students started screaming.
Then it was over and the whole assembly hall was tinted a pale blue
Nagisa looked around as the rest of the students hesitantly began to look up.
The first thing that caught his eye was that outside, the birds were frozen.
He gasped, taking a step closer, the door had been blown wide open so it was easy to see outside, and for a second he just thought it was his imagination, but... those birds weren't moving or making a sound. There was just silence.
"Oh, no..."
Nagisa turned back to the robot that was slumped on the ground.
"How did I miscalculate..." She buried her face in her metal hand. "I had everything planned out."
"What are you talking about?!" Professor Bitch snapped, walking over.
"She said she's Ritsu From the Future," Karma said, sliding down the spaceship, and then dusting himself off.
(Future?)
Nagisa stared at Ritsu in awe. "You're from the future?"
Ritsu sighed deeply, nodding. "Yes, but, I have made an extreme error..."
The rest of the students moved closer in, focusing on her until a number of them finally clocked onto the second anomaly in the room; the giant yellow octopus looking at the creature in teachers' robe.
"WHAT THE HELL IS THAT THING!?"
Koro-sensei flinched back and turned purple from panic. "Ah! No, I'm a teacher! A member of the faculty. No need to worry!" he spoke at nearly Mach 20. "Don't panic!"
The rest of Class E hunched over in defeat.
"Well, there goes that Ten billion." Hiroto sighed, looking blue like the rest of the class.
"I had a great plan lined up and everything," Kataoka despaired.
"Will someone please explain what's going on?" Student Council President, Asano, stepped forward, crossing his arms. His four friends and fellow council members standing behind him.
Koro-sensei stopped rambling and grew still, while Karasuma sighed and pinched the bridge of his nose.
"I'm from the future," Ritsu said calmly, standing up. "But, not the kind of future you'd like." She smiled sadly and looked around the room. "You may find this hard to believe, and I won't blame you, but I came here to the past to stop a disaster from happening fifteen years from now." She pointed to her ship. "And that is my time machine."
The school was silent, staring at the ship in amazement.
Then the homeroom teacher of Class B, Etsuki-san, a plump woman with slicked-back hair, stepped forward. "What do you mean save the future?"
Ritsu curled her hands into fists and touched her bracelet. "Koro-sensei...That yellow man over there is a human mutation." She projected a large holograph of a wasteland future with a city in ruins. "In fifteen years, the research that created him with spur a virus which will infect 75% of the world's population."
The projection showed mutated... they didn't even look human anymore, they were a cross between a squid and some kind of savage monster.
"I'm gonna be sick..." whispered a girl behind Student Council Secretary Ren.
"It will be named Virus D26, created on May 6th," Ritsu told them, closing the projection. "Once the virus takes hold of you, you become feral..."
"Ah, fuck," someone gasped.
"Shit," whispered Professor Bitch, lowering her gun.
Even Karasuma looked horrified. "My God..."
Tsuchiya, a pretty, long-haired, girl from Class A shoved herself to the front. "Then how are we supposed to stop it?!" she snapped, trembling from anger. "We're Junior High kids!"
Nagisa's stomach twisted, but then he looked at his class and was reminded what a group of Junior High kids could do.
Ritsu eyed her calmly. "Well, actually, I never intended to involve anyone outside of E Class."
Tsuchiya bristled along with the rest of the students.
"WAIT, WHAT!"
Ritsu smiled sheepishly. "As I said, I miscalculated." She turned around to face E Class. "Everything you..." She faltered, smiling a little more softly. "We, accomplished, set up the events of the future." She looked back at the other students. "After much thought, I realised the past is the key to saving the future!" She grinned. "So, I collected memories from everyone who had some kind of impact on our Class."
Nagisa's brow furrowed. (Wait, she said our class, so was she one of their classmates in the future?)
"Our class...?" Isogai repeated, frowning.
Ritsu nodded and showed another video, fast-forwarded pieces of footage of them.
"Hey! That's us!" Okajima yelled, pointing at the projected.
"We noticed, dumbass!" one student heckled.
Okajima's cheeks flushed, glaring.
"Hey! Shut up, shithead!" Terasaka waved his fist.
"Be quiet, all of you," Karasuma crossed his arms.
Ritsu ended the projection. "When I gathered all the memories I needed, I compiled together along with some relevant security footage and then separated everything into 47 episodes." She smiled brightly. "And, took a few artistic liberties in the creative process."
(Episodes? Artistic liberties?)
"The purpose was to use them to explain the next coming year," Ritsu said. "I've already examined the footage over ten thousand and twenty times..." Her gaze lowered in shame. "But I lack the capacity to find a solution." She looked at Class E. "Finding solutions to illogical and presumed impossible scenarios was always Class E's speciality."
"Seriously?" Takada exclaimed in disbelief, but nearly everyone ignored him.
"We need to review the footage, examine the details we may have missed, and help save the future," Ritsu smiled at them with determination. "Will you help?"
"What kind of class would we be if we didn't help a fellow classmate?" Koro-sensei said warmly, placing a tentacle on her shoulder.
Ritsu's smile brightened. "Thank you!"
"Again, SERIOUSLY?"
Nagisa shared a look with Class E, as their faces began to light up. "Yeah, we'll help."
"Yeah, let's do this!" Rio shouted, jumping up.
"We were going to try and save the world anyway." Sugino shrugged, smiling.
"Uh, can we pass?"
Ritsu and the rest of Class E looked at the other students.
The Student Council didn't voice their agreement but they were silent like the rest of the students, unsure of what they were getting themselves into.
Ritsu smiled sheepishly, turning to them. "Unfortunately we're trapped in this assembly hall together."
It took a second for that to sink in.
"WAIT, WHAT!"
Ritsu rubbed the back of her neck, embarrassed. "Do you remember that blinding light?" She sighed. "That was the time bubble activating which seals us in this hall frozen in time for three days..."
Nagisa tensed, looking back outside at the still birds, as a bead of sweat dripped down his cheek.
The rest of the students looked in the same direction.
"Oh, shit she's right!"
"I don't even have cell phone reception!"
"This has to be a dream!"
A majority of the students dissolved into screaming.
"Now let's all just calm down, students!" Etsuki tried to placate.
"I'm getting out of here!" Tanaka made a run for the door.
"Hey wait a minute!" Ritsu yelled.
When Tanaka hit the edge of the time bubble it moved like jelly and threw him across the room.
"AHHH!" Tanaka was flying through the air.
"I got him!" Koro-sensei reached out and quickly caught the chubby boy in a cat's cradle of tentacles.
"What the—AHH!" Tanaka flailed about in the tentacles. "What the hell are these things?"
Karma laughed. "Someone get a picture!"
Ritsu sighed, shaking her head. "Escape isn't possible, not even for me."
"Then why did you activate it?" Asano rebuked sharply, narrowing his eyes.
"It's an automatic whiplash of the time travel," she explained. "Once landing the bubble activates within five minutes. The only thing I was able to alter was how far it covers." Ritsu sighed again. "I originally set the coordinates for the Old Campus building." She scratched her head. "And this assembly hall is practically the same size."
At the back Koro-sensei gently placed Tanaka on the ground, the boy let out a scream and ran back to where the rest of Class D was.
"So the only way to get out is to wait the three days?" Nagisa said, frowning.
Ritsu nodded. "This does work as an advantage as well, since it means we'll be able to watch all the episodes in two days." She clapped her hands together excitedly.
The other students weren't as excited.
"Um, how long exactly are these...episodes?" Okada asked timidly.
Ritsu tapped her chin. "Approximately 18 to 23 minutes, which means it should take only 24 hours or less to finish them all if we include bathroom breaks."
"TWENTY FOUR HOURS!"
"Well, obviously we'd need to divide the time evenly," Ritsu added helpfully.
Nagisa clutched his head like it was going to overload.
"So, are we doing this or what?" Karma spoke up, stepping forward with his hands stuffed in his pocket. "Because if we've got to get through that many episodes, we need to get on with it."
“How are you so calm about this!” Another student yelled.
The whole school was silent for a moment.
"We still don't know if we can trust you," Professor Bitch said darkly, narrowing her gaze.
Ritsu stiffened but then smiled. "True, but considering you all outnumber me to one, and you have Koro-sensei on your side, I doubt I'll pose much of a threat to him protecting you."
Koro-sensei nodded firmly, standing next to Nagisa.
Professor Bitch faltered, staring at her warily. "Okay...good point." She stuffed her gun back into her white blazer. "But, try anything funny and you're scrap parts."
Ritsu bowed her head respectfully. "Yes, of course."
"Yeah, but wait!" Araki pointed at Koro-sensei. "You haven't explained what that t-thing is!"
"I'm a teacher!" Koro-sensei protested.
"Like hell you are!" said Ono Kensaku, the homeroom teacher of Class D.
"Yes, um, what are you?" Etsuki asked nervously.
The rest of the E class stood on guard.
"That'll be explained in the first episode," Ritsu said, smiling. "But first, I need one last piece." She walked over to a flustered Koro-sensei. "Sir, I know this is an intrusion, but I need some of your memories to complete the memory bank." Her eyes were almost pleading. “It could be the key to stopping all this.”
The rest of the students were struck silent while Koro-sensei stared down at Ritsu thoughtfully for a moment.
“That’s quite an ask,” he mused, rubbing his rounded face.
“I know, and you have no reason to trust me, but…I’m hoping you will,” she smiled faintly. “Maybe even on account of a promise you made to someone,” she said quietly. “And I know you don’t break your promises.”
That made him pause, and he stared at her for a while longer and then chuckled. “Interesting indeed!” He was bright and sunny. "...Yes, of course," he said warmly, nodding. "Take whatever you need."
Ritsu nodded and then pulled out a thin-looking Smartphone. "Please stare directly at the screen for two seconds."
Nagisa watched in fascination along with the others as Koro-sensei stared at the phone, then after exactly two seconds, there was a flash of light from the camera.
"There," Ritsu said, lowering the phone. "Thank you, sir, that's all I need." She looked over at the rest of the students. "Now, are there any chairs or mats in close proximity that we can use?"
There was another small hesitation, as everything started to sink in.
"There are mats stored underneath the stage." Asano sighed, scrutinising Ritsu intently. "The chairs are stored behind the stage."
"Thank you," she replied, surveying them all. "Well, we better start setting up."
Nagisa blinked a few times before he realised she wanted them to all go get the mats and chairs. "Oh, right yeah!" He looked over at Kayano. "We can go get the mats underneath the stage."
Kayano's smile seemed a little forced. "Oh, right, yeah!"
(Weird...)
"Let's hop to it, people!" Koro-sensei clapped his tentacles together.
"Right!" E class chanted.
That seemed to knock the rest of the students out of their shock.
"Right, yeah!" Tsuchiya yelled.
"A-Class, help set up the chair!" Asano ordered.
"RIGHT!"
Everyone started moving, making Ritsu smile fondly. "Hmm,oh, Koro-sensei!" she called, turning to the teacher.
"Hmm?" Koro-sensei chimed.
"Would you please help me move my ship out of the way?" she asked, smiling meekly, glancing at the smoking ship in the middle of the assembly hall. "It is taking up room."
Koro-sensei's grin widened. "Of course!"
His large tentacles reached out and lifted the time machine with ease.
"Whoa!" some of the students whispered.
Then, as if finally at their limit, one of the students fainted.