Two days after the sports festival, Akira was in the basement lab, one leg stretched out in a cast that had already started to itch.
Ritsu's unfinished body lay open on the worktable. Circuits, joint frames, and thin crystal lines ran through the chest cavity like a second nervous system.
Ritsu's face hovered on the nearby screen.
"Did you add those Crescent Tears in there too?"
Akira adjusted a filament with a pair of tweezers. The cast bumped against the chair, and he ignored it.
"Yeah. They're not just good for lasers. With the right treatment, their optical properties work as an alternative to normal fiber optics. I can route light through them straight into your artificial neural network."
Ritsu was quiet for a moment.
"Will Erika mind if you give me more Crescent Tears than even her?"
Akira's hands stopped.
"…I don't think so." He thought about it longer than he meant to. "I mean, if we think about it that way, my robots have more gold and platinum than anything I've ever given her. I think."
Ritsu looked confused.
"Emotions are so hard to understand."
Akira let out a breath.
"Tell me about it."
The basement door burst open.
"Akira-kun! Sensei is here to see you!" Koro-sensei floated in with a paper bag held high. "I even brought you some fruit from Hokkaido."
Akira took the bag.
"Oh. Thank you, Koro-sensei."
Koro-sensei's eyes dropped to the cast.
"By the way, Akira-kun… it's been two days. Why are you still in that? I thought your leg healed on the first day."
Akira tapped the plaster with a knuckle.
"Oh, this. Erika punished me again."
"Again?" Koro-sensei sounded almost impressed. "You have been punished a lot these days."
Akira nodded, completely serious.
"Well, because I'm being reckless. I know. But I like being punished."
The lab went silent.
Koro-sensei froze. On the screen, Ritsu also froze.
Akira realized what he had said a second too late.
"Wait. That came out wrong." He sat up straighter. "What I meant was, she only punishes me because she cares about me and worries about me, right? And I get to spend more time with her whenever she punishes me, so it's fine. She likes it. I like it. Fair is fair."
Koro-sensei recovered first.
"Sensei understands. As long as both of you like it, it's all right. But try not to be too reckless, okay?"
Akira looked serious.
"Don't worry, Sensei. I will only be reckless with myself."
Koro-sensei deadpanned.
"That's bad too."
Koro-sensei leaned over the table, curiosity already replacing the lecture. Tentacles hovered above the open chassis.
"What's this? A new project?"
Akira glanced at the screen, then back.
"Keep it a secret. It's a body for Ritsu."
Koro-sensei's face lit up.
"What? Really?"
Akira nodded.
"Yeah. Ritsu asked me herself."
Koro-sensei turned to the screen.
"Is that true, Ritsu-san?"
Ritsu nodded.
"Well… I wanted to help my classmates more. So I asked Akira-kun for his help."
Koro-sensei wiped his eyes at once.
"You have grown up. Sensei is proud. Is there any way Sensei can help?"
Akira pulled a blueprint closer and pointed.
"Here. You can help me align these optical fibers, connect them to the circuits, and tighten the screws according to this."
"Leave it to me!"
Koro-sensei dove into the work immediately, tentacles moving with cheerful precision.
He did not, even once, stop to consider that he was helping build a body that could one day be used to kill him.
They worked in silence for a while, Koro-sensei's tentacles moving along the blueprint with surprising care.
Then Akira spoke without looking up.
"Koro-sensei, how did it go after the game? I was stuck in the infirmary and didn't get to ask the others much. Did everything go well?"
"Yes." Koro-sensei tightened a screw. "Asano-kun kept his promise not to report Isogai's part-time job. Everyone was happy. They even had a small celebration afterward."
Akira made a disappointed sound.
"Well. Too bad I got stuck in the infirmary."
"Oh, right." Koro-sensei lifted a tentacle, as if he had just remembered something. "Karasuma-sensei told me to give you a message. Apparently, the principal told him to tell you, 'Not a bad move. But keep in mind that hacking is illegal.' …So, what is that all about?"
Akira kept his eyes on the circuit.
"Oh. That." He clicked a connector into place. "After the match, I was stuck in the infirmary and got bored, so I hacked into the principal's office cameras. I came across him beating the exchange students. Even the kung fu guys. So I sent him the video anonymously. 'Two can play that game.' That's probably what he meant."
Koro-sensei froze.
"Wait. He beat them up?"
Akira shrugged.
"Yeah. The principal is strong."
Koro-sensei was quiet for a second.
"…So that's how it is. Well. It is illegal."
Akira shrugged again.
"There's no way he can prove it was me. Besides, I'm not really blackmailing him. I just gave him back his lost property. That's all."
Koro-sensei sighed and went back to tightening the screws.
A few minutes passed.
Then Akira glanced over.
"By the way, Koro-sensei. Don't you want to ask me something?"
Koro-sensei tilted his head.
"What is it?"
Akira looked eager.
"You know… the thing."
Koro-sensei looked even more confused.
"The thing?"
Akira waited expectantly.
"You know. Something that's supposed to be there. That's missing."
Koro-sensei thought hard.
"Is it about the honey toast?"
Akira snapped.
"No, it's not about the honey toast. My heart. I'm talking about my missing heart."
Koro-sensei finally remembered.
"Oh. That."
Ritsu's screen flickered.
"Wait. Your heart is missing?"
"Don't worry about it." Akira waved a hand at her, then looked back at Koro-sensei. "Anyway, I'm sure you're curious about it, right?"
Koro-sensei's voice softened.
"Sensei is curious. But Sensei can't simply inquire about private matters."
Akira pressed.
"But you want to know, right?"
Koro-sensei looked sympathetic.
"It's all right, Akira-kun. Sensei will keep your secret. You don't need to tell me."
Akira leaned forward.
"But I can tell you. If you really, really want to."
Koro-sensei went still.
Then his shoulders dropped.
"…Akira-kun. You just really, really want to tell me your backstory, right?"
Akira beamed.
"Yes."
Ritsu and Koro-sensei looked at each other.
Then they looked at Akira.
"All right," Koro-sensei said. "Then you can tell us about it."
Akira sat up straight at once, cast and all.
"Okay. It happened a long time ago. I was nine years old at the time—"
He stopped.
The excitement on his face shifted into a better idea.
"…You know what? I actually wrote a novel about it. If you want, you can read it."
He reached under the worktable, pulled out a slim first volume, and held it out.
"It's a light novel. I embellished a few things and turned it into a fantasy space adventure. Other than that, it's my story."
Koro-sensei accepted it with both tentacles. His eyes landed on the cover.
"It does look like Akira-kun and Erika-san on the front. Then… Sensei can read it?"
Ritsu leaned closer on her screen.
"Can I too?"
"Sure," Akira said. "Both of you can."
That was the last thing he got out of them for a while.
Koro-sensei opened the book. Ritsu pulled the text onto her display.
Both of them disappeared into the first page.
---
Koro-sensei closed the first volume of Orion: At the End of Stars and immediately burst into tears.
"Bwah! AHA! HA! This is such an emotional story! For such a thing to happen to two young children!"
On the screen, Ritsu was crying too.
"Yes. Especially the final part. When Lyra had to do that. Akira-kun… did that really happen?"
Akira scratched his cheek.
"Mostly. Well, there were no werewolf space mercenaries, and the other space-fantasy stuff didn't happen. But that's basically what happened to me."
Ritsu sniffled.
"So, did Erika-san really say that?"
Akira looked away.
"Oh. That… I made that part up. I lost consciousness, okay? I don't know what happened after that. And she got really mad when she found out what I wrote."
Ritsu wiped at her display as if that would help.
"So… is Erika-san really a vampire?"
Akira finally remembered that, he wrote Erika's true identity as a vampire part in the novel.
"Nooo. She is not."
Ritsu looked closely at him.
"Are you sure?"
Akira nodded furiously.
"I am 100% sure she is not a vampire."
Ritsu stared at him.
"Hmmm. Still suspicious. So your heart is a machine."
Akira nodded, placing a hand over his heart.
"Yes. It is."
Koro-sensei held the book to his chest, still watery-eyed.
"Akira-kun, by the way, your writing is really good. You should publish it."
Akira considered that.
"Hmm. Maybe I should…"
Ritsu leaned closer.
"Akira-kun, do you have a second volume?"
Akira smiled.
"I do."
He reached under the table and set a small stack of books beside the first one.
Ritsu's eyes moved from cover to cover.
"Wait. Why does each book have a different girl on the front?"
Akira answered far too easily.
"Because I left Erika and went on an adventure and met different girls."
Koro-sensei picked up the second volume.
"Akira-kun. How many girlfriends do you have?"
Akira immediately answered.
"Just one. Just one, all right? They're just my friends."
"But here—"
Koro-sensei's phone rang.
He answered at once.
"Oh, Karasuma-sensei, what is—"
He listened.
The yellow drained out of his face.
Black took its place.
Akira sat up straight.
"…Whoa. What happened? Why are you angry?"
Koro-sensei was already turning toward the door.
"I will be back."
He left at Mach 20, the basement air snapping shut behind him.
Akira stared at the empty doorway.
"Why did he drop a Terminator line and run away?"
"I will check," Ritsu said.
The basement door opened again before she could finish.
Erika came in with an armful of cold drinks, looking completely confused.
"What happened to Koro-sensei?"
Akira blinked.
"What do you mean?"
"He went speeding past in black," Erika said, setting the bottles down. "But when he saw me, he said, 'Sensei is so proud of you,' and just ran off. I have no idea what he meant—"
Then her eyes found the light novels.
Her voice dropped.
She smiled, but it didn't reach her eyes.
"You showed him that."
Akira lifted both hands.
"Wait. I was trying to explain my missing heart, and this came up. It's—"
"I found out what happened," Ritsu said.
Both of them turned. One looked annoyed. The other looked grateful.
Ritsu continued.
"Apparently, some of our classmates were parkouring through the city and had an accident. It involved an old man."
Akira and Erika had the same thought at the same time.
Oh. That part.
"The old man is hurt," Ritsu said. "Karasuma-sensei and Koro-sensei are already on the scene."
Akira started to stand, cast and all.
"Seems like we have to go there and look."
Erika caught his wrist.
"Before that, tell me exactly what you told them."
Ritsu, helpful as ever, added,
"Erika-san, did you actually say, 'Let's meet at the end of the stars,' to him?"
Akira's face went pale.
"Wait, that's—"
Erika's grip tightened.
"Seems like we have to talk."
"Noooooo!"
For a short while, only Akira's screams filled the basement.
It was hell.
Tickle hell.
And with one leg in a cast, he couldn't even run away.
Akira did not recover from that for quite some time.