The final bell cut through the halls, and I was gone before anyone could stop me.
Room 722 felt colder than yesterday. I dropped my bag in the corner and paced once around the room.
Old mystery novels lined the shelves. Christie beside Doyle beside Keigo Higashino, jammed together with no system. On the back wall hung a faded poster, torn nearly in half:
MYSTERY CLUB NEVER DIE.
I winced at the grammar. One corner had been ripped clean off.
This room used to matter. But there were no journals. No photos. No records of past members. Someone hadn't just shut the club down. They'd scrubbed it.
On the bottom shelf sat a box: 5,000-piece landscape jigsaw. The cover was faded—sun-bleached greens and a wash of pale sky. The kind of puzzle that dared you to waste your life.
I opened it anyway, dumped the pieces across the table, and started sorting edges.
The border was half done when the door creaked.
Hani slipped in, cheeks red from the September wind, two cans of Zero Cola in her hands. She tossed one my way. I caught it without looking.
"Didn't think you'd be here early," she said, dropping onto the sofa beside the table.
"I like it here," I said. "Nobody bothers us."
She smiled. "Avoiding people again. Mind if I take the sky pieces?"
I slid a pile toward her. Our fingers brushed for half a second. We both ignored it.
For a while, there was only the soft clack of pieces and the hiss of cans opening.
"You know the vending machine on the second floor?" Hani said. "Kick the bottom left corner twice. It spits out two cans."
I glanced at the extra drink. "So that's why you brought spares."
"You got me." She snapped a piece into place. "Three times last week."
She studied the puzzle. "Remember that huge one I brought to the acacia tree? The thousand-piece landscape?"
I remembered. She'd lugged it all the way up the hill in her backpack, pieces rattling in a plastic bag.
"We were halfway done when that cat came out of nowhere," she said.
"Jumped right through the middle of it," I added. "Scattered pieces everywhere."
"Then that girl showed up, panicking because her cat ran off." Hani smiled at the memory. "What was her name again?"
"Doesn't matter. You felt bad, so we had to find it."
"You found it," she corrected. "I was just following you around while you pointed out paw prints in the dirt and fur on the fence."
I shrugged. "It wasn't hard. The cat left a trail."
"You made it look easy." She slid a piece into the lowest row. "I just tagged along."
"You spotted it first," I said. "Hiding under that shrine."
She laughed softly. "Because you told me where to look."
The memory settled between us, comfortable and familiar.
"You still build from the bottom up," I said, watching her hands.
"It works," she said simply, fitting another edge piece into place.
---
The door slammed open hard enough to rattle the windows.
Michi stormed in, clutching a shredded poster. "We're official," she said. Her voice was sharp, but it wavered underneath. "SAO approved us this morning. We need a faculty advisor and five members by the end of the term. Or we're dead again."
She pinned the remains of the poster to the wall. Someone had scrawled over the club name in black marker:
HQTQH9 U748.
Hani tilted her head. "That's not even pretending to be random."
Michi laughed once, brittle. "Second incident this week. First the padlock, now this."
Hani looked at her. "Padlock?"
"Nothing," Michi said too fast. "Not important."
The weight of the six-digit combination lock pressed against my blazer pocket.
Michi went on. "I put up five posters yesterday at five p.m. By six-thirty this morning, every one of them had that exact string."
I stopped sorting pieces.
I took a photo with my phone and stared at it.
Not a riddle.
Old cipher, maybe. Something simple.
The longer I looked, the more wrong it felt.
---
Three sharp knocks cut through the room.
The door opened before anyone answered.
A tall middle schooler stood there, backpack slung low, eyes wide.
She glanced at Hani and me, then back to Michi.
"Michi-senpai… I need help."
Michi's shoulders loosened. "Hina. Come in."
The girl stepped inside, stiff with nerves. For a split second, her fingers tapped a quick rhythm against her bag strap before she stopped herself.
"I'm Hina Momose," she said, bowing slightly. "Middle school student. I heard the Mystery Club was back."
Hani leaned toward me. "So much for 'nobody bothers us.'"
Hina caught the comment and her face fell, just slightly. "I'm sorry—if this is a bad time, I can come back."
The way she said it was so genuinely small that even I felt bad. Hani waved her off immediately. "No, no—stay. I was just teasing."
Hina's shoulders relaxed. She gave Hani a quick, grateful smile—open and unguarded—before turning back to her bag.
She pulled ten cards out and laid them on the table. They looked like miniature license plates, printed in neat typewriter font.
M 24 NWO
O 20 HSR
M 23 EBM
O 20 UNA
S 20 DYB
E 22 RET
H 17 TEL
I 12 HCA
N 6 ETF
A 14 IHS
"They've been appearing in my locker," she said. "One every morning. Ten days straight."
She tapped the first column. "This part I figured out. 'Momose Hina.' My name."
Her hands trembled slightly.
"It didn't seem like a big deal at first, so I just ignored it." She paused. "Then the last one came with a pressed flower. And a photo."
Hani leaned closer. "What kind of photo?"
"Me sleeping in the library. Taken from behind."
The room went dead silent.
"It's like someone's trying to impress me," Hina said. "But it feels obsessive. I need it to stop."
I glanced at the puzzle on the table. The bottom rows were complete, locked in place. Hani always built from the ground up.
The cards were arranged the same way.
Low to high.
So that's how it is. The thought clicked into place so cleanly.
I turned back to the puzzle. "It's just a small case. You're worried over nothing."
Hina stiffened. "But I can't afford any distractions. I need to make it into the elite section—"
"Eiji." Hani cut in, looking straight at me. "No case is too small if someone's desperate enough to ask for help."
That stopped me. She'd said the exact same thing back then—when I'd dismissed that girl's missing cat as trivial. Before we spent the afternoon tracking paw prints and checking under shrines.
Michi leaned forward. "She's right. And with all the sabotage we've been dealing with since this club started, we might as well prove they don't get to decide what we take on."
She turned to Hina. "We'll take it. First official case."
Hina exhaled. Relief washed over her face.
I let out a slow breath. "Fine."
I glanced at the cards one more time. "Then start by asking Yuto Kijima to stop."
The room went silent.