Rei sat cross-legged on the cold floor of his room, the dim yellow bulb above him flickering softly as if it, too, was tired of watching him think. The metal briefcase lay open in front of him, its dark interior swallowing light, while the folded paper rested beside it like a secret that refused to speak clearly. His fingers hovered over the edges of the page, but he didn't unfold it again. He already knew every word written on it. He had reread it so many times that the lines were burned into his thoughts.
His mind felt heavy, filled with unanswered questions, strange possibilities, and a growing fear that whatever he had stepped into was far bigger than him.
But then, suddenly—
Knock. Knock.
The sound echoed sharply through the quiet apartment.
Rei flinched.
He slowly stood up, walked to the door, and turned the lock. As he opened it, he was met with a familiar face.
It was Koma.
She stood there holding her phone, her expression unusually serious, as if she was carrying news that would change something important.
"Rei," she said softly, "Kai Satome and Chuya Korose are coming to live with us for a while. Your mom is going to my other apartment where my parents live."
Rei blinked.
That meant… all four of them would be together now.
A strange warmth flickered inside his chest. He didn't know why, but it felt like the universe had just nudged him in a direction he hadn't noticed before.
Wait… this is actually a very good thing, he thought. If they're all here… maybe I can finally tell them. Maybe we can solve this together.
Before he could reply, Koma stepped inside, closing the door behind her.
They barely had time to process the news before another sound cut through the air—
Ding–dong.
The doorbell rang.
Rei and Koma looked at each other.
"That must be them," Koma said.
Rei walked over and opened the door.
Standing there were Kai and Chuya, both wearing their usual lazy grins.
They stepped inside and immediately started looking around exaggeratedly.
"Hmmm," Kai said slowly, glancing between Rei and Koma, "a couple having their private timeee… how many kisses did you two have, huh?"
Chuya snorted in laughter.
Koma instantly grabbed Rei's arm tightly. Her face turned red as she looked away.
"Ah—no!" she said nervously. "We were just discussing how much fun we're going to have now that we're all together!"
Rei exhaled sharply.
"Guys," he said, his voice suddenly serious, "close the door. We don't have time. I need to talk about something very important."
Chuya raised an eyebrow.
"Okayyy," he said, dragging the word, "but tell us what happened ASAP."
He closed the door behind him and leaned against the wall.
The room went quiet.
Rei took a deep breath.
Then he told them everything.
About the strange man.About the briefcase.About the cryptic instructions.About the puzzle.About the uneasy feeling that something dangerous and unknown was slowly moving around his life.
As he spoke, Koma listened silently, her grip on his sleeve tightening little by little. Kai's playful smile faded into a thoughtful stare. Even Chuya, usually the loudest one in the room, stayed quiet.
When Rei finally stopped, Chuya broke the silence.
"No way…" he muttered. "All of this actually happened?"
Kai crossed his arms. "Rei… are you sure that page has an address? And did you get any clue from it yet?"
"Yes," Rei replied firmly. "I am damn sure. And no, I didn't get any clue right now. That's why I told you all about this. So we can figure it out together."
Koma looked at him, then nodded.
"Rei, show us that case ASAP," she said. "Even though Chuya is very talkative, he's actually a nerd in science. He might understand something."
Chuya gave a proud shrug. "Hey, don't expose me like that."
Rei led them into his room.
The briefcase lay waiting.
He opened it fully, revealing the strange vials, the metallic components, and the carefully arranged compartments.
All three of them leaned closer.
Chuya stared at the contents for a long moment.
Then he slowly leaned back.
"No way I can understand this," he admitted. "It's too advanced for me. Whatever this is… it's beyond normal science."
Rei's heart sank slightly.
"Anyway," Chuya continued, "just show us that paper. We can try to solve the puzzle and get that location."
Rei picked up the folded page and handed it to them.
They read it carefully.
After a few seconds, Rei spoke again.
"It isn't about putting those vials near three windows," he said. "It's about three windows themselves."
Koma frowned.
"Wait… let me read that puzzle once again."
She unfolded the paper fully and read it aloud, exactly as it was written:
"Place the clear solution beneath three silent windows.Do not let it face the narrow passage."
The room fell silent.
The words hung in the air, heavier than they looked.
Chuya rubbed his chin. "Three silent windows… narrow passage… that doesn't sound like a lab instruction."
Kai's eyes narrowed. "It sounds more like a location clue."
Rei slowly nodded. "That's what I thought too."
Koma walked toward the window of Rei's room and looked outside.
"What if… 'three silent windows' means three buildings with sealed or unused windows?" she said. "Or maybe three towers?"
Chuya snapped his fingers. "Or three old factories. A lot of abandoned factories have sealed windows."
Kai added, "And 'narrow passage' could mean a tight alley or underground tunnel."
Rei felt a strange mix of fear and excitement rising inside him.
For the first time, the puzzle didn't feel impossible.
It felt… alive.
Like it was waiting to be understood.
They all stood there, staring at the paper, realizing that whatever Rei had unknowingly stepped into was no longer just his problem.
It was theirs now.
And somewhere out there, hidden beneath three silent windows and away from a narrow passage, something important was waiting.
Something that had already begun to change their lives.