Chapter 1: The Girl at the Door
The rain had stopped an hour ago, but the scent of wet asphalt lingered in the air, mixing with the sterile tang of fluorescent hallway lights and the faint rust of old apartment walls.
On the thirteenth floor of the Yakushi Heights apartment complex, a boy sat in silence—legs crossed, body slouched, and eyes fixed on the ceiling as if trying to memorize each crack in the plaster.
Arai Kazuki had grown used to silence. He welcomed it. It didn't ask questions or demand explanations.
It simply filled the room like fog—constant, weightless, indifferent. That was how he preferred his life: quiet, predictable, and entirely void of surprises.
The room around him was bare, but not dirty. A futon folded into the corner, a compact desk cluttered with notebooks and empty instant noodle cups, and a shelf of dog-eared paperbacks were the only signs that someone lived here.
The window was cracked open just slightly, letting in the scent of the rain and the distant hum of city life.
Kazuki didn't believe in comfort. He believed in efficiency. There was a rhythm to his life, a structure built from routine: wake at six, attend school without speaking, work part-time jobs in silence, return to the apartment, eat instant meals, and read until sleep finally overtook him.
It wasn't happiness, but it was safe. Predictable. No chaos. No people.
It was a Tuesday evening. Kazuki had just returned from his shift at the bookstore—his second job, one he tolerated because it kept him away from people most of the time. He hadn't spoken more than five sentences that day.
He preferred it that way.
Then came the knock.
It was soft, almost uncertain.
Kazuki frowned. He wasn't expecting anyone. No one ever came to see him—not classmates, not coworkers, and definitely not family. For a few seconds, he remained frozen on the floor, wondering if it was just his imagination.
The knock came again, firmer this time.
Kazuki stood slowly, dragging his feet across the tatami. He reached the door, hesitated, then unlocked it with a practiced motion, prepared to send away whatever salesman or delivery error had dared breach his sanctuary.
Instead, the door slid open to reveal something—someone—that made his mind stall.
A girl. Tall. Maybe a few centimeters taller than him.
She stood there in a soaked uniform: white blouse clinging uncomfortably to her skin, red tie slightly loosened, and a navy pleated skirt that ended mid-thigh.
Her short brown hair was tied in a high ponytail with a red ribbon, strands damp from the rain. She held a small red school bag in one hand and looked at him with eyes that were strikingly golden—a shade between honey and sunset.
And she smiled.
"Hi!" she said, as if they were old friends.
Kazuki blinked. He opened his mouth to respond, but no words came out.
"You're Arai Kazuki, right? Room 1302?"
He nodded slowly, still processing.
She shifted the bag onto her shoulder. "I'm Sena Ayaka. Looks like we're roommates now!"
The silence that followed was long and awkward. Kazuki could hear the creak of a distant elevator, the dripping of water from her bangs, and the sudden thumping of his own heart.
Roommates?
He looked over her shoulder, expecting someone—anyone—to pop out and explain the joke. A camera crew maybe. Or a manager apologizing for the mistake.
But there was no one.
Kazuki's voice was barely a whisper when he finally found it. "This must be a mistake."
Ayaka tilted her head, unconcerned. "The landlord said the same thing. But all the paperwork went through, and apparently they double-booked the unit."
"He offered to cancel, but... I didn't really have another place to go. So I asked if I could stay."
Kazuki stepped back. Instinct. Not fear, not exactly—but discomfort. This apartment, small and confining as it was, was the only space he could control.
Ayaka took that as an invitation and stepped inside.
The scent of her shampoo cut through the musty air, a floral contrast that made the room feel immediately smaller. She looked around, hands on her hips.
"Wow. You really live like this, huh?"
He didn't answer. Just stood there, heart pounding, throat dry. There was something almost surreal about her presence. The way she moved. The way she smiled.
Ayaka set her bag down. "Don't worry, I won't take up much space. I've lived in tighter spots. And I'm not picky."
Kazuki finally found his voice. "You can't just... move in."
She looked at him, still smiling, but softer now. "I know it's weird. But I'm really not here to cause trouble. Just... give me a chance?"
He wanted to say no. Wanted to slam the door and rewind time and pretend none of this had happened.
But those eyes—bright, sincere, stubborn—made it impossible.
And for reasons he couldn't explain, Kazuki nodded.
...
That night, Kazuki lay awake on his futon, listening to the soft rustling from the other side of the room.
Ayaka had claimed the corner by the window, using her backpack as a pillow and an emergency blanket from her bag. She hadn't asked for his help. She just made do.
He kept his back to her. Eyes wide open. Mind racing.
His world had been a single color for so long. Muted, cold, safe.
Now, someone had stepped in and painted over it with something louder, warmer, and utterly unpredictable.
He didn't know whether to feel terrified or grateful.
All he knew was that nothing would be the same again.
And maybe—just maybe—that was okay.
The following morning came too quickly. The light filtered in through the half-open blinds, casting narrow stripes across the tatami. Kazuki rubbed his eyes, still in disbelief that someone else was breathing the same air in his apartment.
She was already up.
Ayaka stood by the window, stretching with a yawn that filled the room with her presence. Her uniform blouse was wrinkled, but she didn't seem to care. Her ponytail was slightly loose from sleep, giving her a more natural, unguarded look.
"Morning," she said cheerfully.
Kazuki nodded mutely, brushing past her to wash up. Everything about the apartment felt smaller now—crowded with a presence that didn't belong. Or perhaps... one he simply wasn't used to.
They didn't speak much during the morning routine. Ayaka didn't seem bothered by the silence. She hummed to herself while combing her hair, and Kazuki avoided eye contact while brushing his teeth.
When it came time to leave, they stepped out of the apartment together—something Kazuki had never done with anyone before. As they walked toward the elevator, Ayaka leaned in slightly.
"You know," she said, "you don't have to talk a lot. But it's okay if you do."
He looked at her, startled by the simplicity of her words.
She smiled again. That same warm, inviting smile that made something unfamiliar twist in his chest.
The elevator dinged, and they both stepped inside. As the doors closed, Kazuki realized something that should have terrified him:
He didn't hate this.
Not yet.
And that realization—small and quiet as it was—might have been the first step toward everything changing.
By the time they reached the school gates, Ayaka had already greeted three people, waved at a teacher, and skipped ahead to avoid being late. Kazuki remained behind, watching her from a distance.
She was like sunlight through a window he'd forgotten he had.
And no matter how much he tried, he wasn't sure he could close it again.