Prologue

The statute of limitations for crimes defined by the Code of Criminal Procedure is fifteen years.

Then, how many years is the statute of limitations on love?

Shizuishi Kiyoko pondered this as she stared absently out the Shinkansen window at the receding expanse of Kyoto Station.

Shizuishi Kiyoko, seventeen years old. Born and raised in Kyoto, on that sunny May day, the girl left her home for Tokyo with a firm resolution in her heart.

Ten years ago, she had made a single promise with a boy who had come all the way from Asakusa, Tokyo. A full decade had passed since that boy spent a year in Kyoto before returning home.

And on this day, Kiyoko had set out on a journey to confirm whether that promise still held true.

Was her promise with the boy still valid?

————Without finding an answer to that question, the Shinkansen arrived in Tokyo.

"Your homeroom teacher, Ogata-sensei, is currently attending a meeting, so I will be overseeing your transfer procedures in her place—For now, please write your name and address on these documents."

A female teacher in her mid-thirties solemnly walked her through the transfer process. Prompted by the teacher, Kiyoko was just signing her name to the paperwork when the door to the after-school staff room abruptly swung open.

"'Scuse us!"

A boy with a deepened adolescent voice and a lively-looking girl strolled into the room.

In that instant, Kiyoko's heart gave a massive leap.

————Kouya-kun!

Beside Kiyoko, who had suddenly begun acting highly suspicious, the female teacher blinked in surprise.

"Oh, Torame-kun, Shiga-san."

"Do you know where Ogata-sensei is?"

"She's in a staff meeting right now. Did something happen?"

"Well, a locker in the classroom kinda got busted..."

"Did you two break it?"

"No way! It just broke on its own!"

"Yeah, it's age-related deterioration!"

The boy and girl vehemently pleaded their innocence in unison.

"I wonder about that. You two are always getting into mischief together, aren't you?"

"We don't do that!"

The boy and girl firmly shot down the teacher's suspicions at the exact same time. The teacher thought for a moment before issuing instructions to the students.

"Go report this to your grade head, Fujiwara-sensei, and ask for his instructions. He should be out on the athletic field."

"Okayyy. Will do."

"Well then, 'scuse us!"

The boy and girl hastily slipped out of the staff room. Once the two were out of sight, Kiyoko timidly glanced up at the female teacher.

"...Um, that boy just now... was that by any chance Torame Kouya-kun?"

"Oh, do you know him? But you've been in Kyoto this whole time, haven't you, Shizuishi-san?"

"Kouya-kun lived in Kyoto for a while in the past."

"Huh, what a surprise... Or maybe not. Torame-kun bounced around a lot because of his parents' circumstances, if I recall..."

"Um..."

After a brief hesitation, Kiyoko steeled her resolve and asked the teacher.

"What kind of relationship does Kouya-kun have with the girl who was standing next to him just now?"

"You mean Shiga-san? She's Torame-kun's childhood friend. I believe they live in the same neighborhood. They're together quite a bit, she and Torame-kun."

"..."

Kiyoko fell into a heavy silence.

————Did I honestly think I was his only childhood friend?

Thinking about it logically, there was no way that could be true. Her childhood friend who returned to Tokyo obviously had childhood friends in Tokyo as well. That was simply reality.

Confronted with this stark fact, Kiyoko was thrown into a state of sheer panic.

"Hawawawawa."

"Shizuishi-san?"

The female teacher frowned suspiciously at the sudden and intense fluster of the transfer student.

"N-No, I am perfectly fine. I am completely fine."

Kiyoko assured the teacher, her face draining of all color.

————This is terrible. Kouya-kun has a precious childhood friend over here.

The two of them had shared such a natural, intimate atmosphere. They called themselves childhood friends, but what was their relationship like now?

Lovers? Were they lovers?

What if that girl was Kouya-kun's girlfriend? That would mean she had selfishly forced her way into his life when he already had a significant other.

Falling into a mild panic while somehow managing to keep her facial expression composed, Kiyoko practically clung to the female teacher as she asked a question.

"Sensei... do you think a pushy, uninvited wife is a nuisance?"

"Where did that come from all of a sudden? That completely depends on the time and place, obviously."

"What if the other person already has a committed partner? What then?"

"That's adultery. It's a crime."

"Hawawawawawa."

"What's wrong, Shizuishi-san?! You look like you're about to cry!"

"I am not bothered by this in the slightest. (Translation: I am immensely bothered by this.)"

"Bothered by what?!"

"I have decided to steel my heart and cheerfully bless the young couple's new journey from the shadows!"

"Like I said, what are you even talking about, Shizuishi-san!"

"I intend to maintain a proper sense of distance so as not to destroy the interpersonal relationships of everyone at this Tokyo school!"

"Huh?"

The female teacher tilted her head. Rather than attempting to understand the psychological state of the girl who had suddenly unraveled before her very eyes, she seemed to decide it was best to focus entirely on finishing the transfer paperwork.

"Well, whatever it is, just stamp your seal next to where you wrote your name, please. That will conclude your transfer procedures."

In a highly businesslike manner, the female teacher urged the newly transferred girl to finish her paperwork.

And so, Kiyoko-san, hailing from Kyoto, became a high school student in Tokyo.