The room stayed in silence after I said the name.
Hina lifted her head too slowly. "Yuto?" She hesitated. "How… how do you know him?"
She already knew the answer. The way she asked told me that much.
"The sender signed his name," I said. "Just not the obvious way."
I leaned over the table and pointed at the cards, starting from the bottom row.
"Read the last three letters. Bottom to top. Right to left."
Hani frowned, following along. Michi leaned closer.
"SHIFT EACH LETTER BY DA NUMBER," Hani read aloud.
I tapped the middle column. "That's the key."
My finger slid to the first column. "Take the letter. Shift it forward by the number beside it."
I didn't rush it. Let them see it.
"M plus twenty-four. O plus twenty. M plus twenty-three."
I straightened. "It spells Kijima Yuto."
No one spoke.
The cold in the room settled deeper. Hina didn't flinch. Not shock on her face—relief. Maybe pride.
Michi broke first. "And you still called it a small case?"
I didn't answer.
Hani smiled, barely hiding it, and nudged my shoulder. The old signal. You did good.
"Maybe he wanted you to solve it," she said. "Let you know it was him. A confession, puzzle-style."
Hina folded her hands together. "We're in the same club. Play With Me. It's new."
Michi raised an eyebrow. "The middle school puzzle club?"
Hani tilted her head. "What kind of club is it?"
"It's just games." Hina shrugged. "Riddles. Brain teasers. A break from everything else."
"Then why come to us?" I asked. "Why not them?"
She tightened her grip on her bag strap. "I'm... too shy to bring it up with them."
I leaned back. "Or maybe you already knew who did it and just came to us for confirmation."
She looked up. "I—"
Michi stepped in before the silence could harden. "Well, regardless, you already know the answer. The question now is how you'll respond."
Hina exhaled softly. "Thank you... I didn't think it'd be solved this fast."
Her gaze drifted to the jigsaw on the table.
"You like puzzles," she said. "Our club room has a lot. If you want to see."
My pulse jumped before I could stop it.
Hani lit up. "That actually sounds fun."
Michi crossed her arms and leaned against the doorframe. "I'll stay. In case someone tries something again."
She glanced at Hina. "And don't steal Eiji from us."
Hina laughed, nodding.
Hani's phone buzzed. She checked it and groaned. "Ms. Song again. She wants me for extra Math Olympiad training after school."
She looked at me, apologetic. "You'll survive without me?"
"I'll manage."
The fog outside pressed closer to the glass.
---
The Play With Me club room was one floor up from Room 722—middle school territory.
The door was bright yellow, painted with cartoon puzzle pieces. A neon sign above it read PLAY WITH ME in bubbly letters.
Inside felt nothing like the floor below.
Colorful cards covered the corkboard. Half-solved cubes lined the shelves. Jigsaw boxes were stacked everywhere. The place buzzed, even empty.
I could already feel time slipping.
"No one's here yet," Hina said, switching on the lights. "They usually come later."
She walked to the lockers along the far wall. Most were bare metal. Hers was covered in light purple stickers. A new combination lock hung from the handle.
One locker stood open nearby.
CHIHIRO was taped across the front.
Inside, car magazines were stacked neatly on the bottom. On the shelf above sat a wooden cipher wheel.
She turned back from her locker and caught me staring at the Pyraminx on the side table. I looked away.
"So, senpai, why'd you join the Mystery Club?" she asked. "You don't seem like the type to join clubs."
I picked up the tetrahedral puzzle. "Didn't get much choice."
She smiled. "You solved the cipher fast. Like it was nothing."
I twisted the pieces. "Puzzle's my hobby."
She watched quietly. "Your eyes light up when you solve things."
I froze for a second. I hadn't noticed. Set the Pyraminx down a little too fast.
She didn't press it.
"What about the old Mystery Club?" she asked instead. "Why did it shut down?"
"I don't know," I said. "Ask Michi."
She tilted her head. "She's got enemies, right?"
I raised an eyebrow.
"Sorry." She ducked her head. "Just curious."
She pulled a small book from the shelf. "You remind me of Chihiro."
"The club leader?"
She nodded, her thumb tracing the book's spine without opening it. "My childhood friend. He was obsessed with puzzles even back then. Went to UK for six years. Then came back last year."
Smart enough to run a puzzle club even as a middle schooler.
"He's the reason I joined," she added. Her gaze drifted to his locker—the one with CHIHIRO taped across the front—before she caught herself and looked away. "It's the only place we still hang out."
My attention drifted to a small board game on a side table.
Hina noticed. "Fanorona. Want to play?"
I hesitated. Then nodded.
We sat across from each other. The room felt smaller now.
She moved first. Fast. Clean.
By the third turn, she'd taken five of my pieces.
Her fingers moved with quiet precision, almost casually, but the pattern was clear. She was reading the board two moves ahead.
"You're not bad," she said. "Most people panic by now."
I studied the board. The pattern was there. Just needed patience.
She captured another piece while I was thinking, then leaned back with a shrug. "Games like this are mostly memorization. I'm better at that than actual problem-solving." A pause. "That's why I'm not one of the top students in my class. But less pressure means more time for puzzles like this, so I don't mind."
The way she said it—casual, almost rehearsed—didn't quite match the look in her eyes.
"You mentioned wanting to make it into the elite section," I said.
She glanced down at the board. "Next year we'll be high school students too. Chihiro's on track for it—top of our class, always has been." Her voice softened, and her fingers stilled on the game piece she'd been about to move. "I just want us to be together next year too."
The board sat still between us. Neither of us moved a piece.
"And Yuto?" I asked. "How are you going to deal with him?"
The softness vanished. She sighed, straightening in her chair. "I'll shut it down. I just hope it doesn't ruin the club."
I slid my stone forward, setting up the trap.
She caught it two moves later.
We reset the board and played again. Then again. Somewhere between the third and fourth game, the conversation drifted—school, clubs, the difference between middle school and whatever the elite section was supposed to be. She asked about Room 722, about Michi, about why someone would sabotage a club that hadn't even started yet. I answered more than I usually would.
She showed me a sliding-tile puzzle she'd been stuck on for a week. I solved it in four minutes. She made me explain every step, then scrambled it and solved it herself in six.
The light through the windows shifted from gray to amber. Hours had passed without either of us noticing.
The door opened.
A tall middle schooler stepped inside, backpack slung over one shoulder.
Hina glanced at him. Something flickered across her face.
The board stayed frozen between us.