The room stayed quiet after I said the name.
Hyein lifted her head too slowly. "Collin?" 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."
Hanni frowned, following along. Minji leaned closer.
"ADVANCE EACH LETTER BY THE NUMBER SHOWN," Hanni 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.
"L plus seventeen. E plus ten. E plus seven."
I straightened. "It spells Collin Jeong."
No one spoke.
The cold in the room settled deeper. Hyein's eyes flickered, sharp for just a moment. Not shock. Relief. Maybe pride.
Minji broke first. "And you still called it a small case?"
I didn't answer.
Hanni 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."
Hyein folded her hands together. "We're in the same club. Play With Me. It's new."
Minji raised an eyebrow. "The freshman puzzle club?"
Hanni asks, "What club was that about?"
"It's just games," Hyein said quickly. "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 don't trust them yet."
After a beat, she added, "And Collin's been… hovering. After meetings. Trying too hard."
She looked up. "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.
Hanni lit up. "That actually sounds fun."
Minji crossed her arms and leaned against the doorframe. "I'll stay. In case someone tries something again."
She glanced at Hyein. "And don't steal Eiji from us."
Hyein laughed, nodding.
Hanni'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 impossible to miss.
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 Room 722.
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," Hyein said, switching on the lights. "They 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.
CHANIEL was taped across the front.
Inside, car magazines were stacked neatly. On the shelf above sat a wooden cipher wheel.
She turned back from her locker and caught me staring at the unsolved Pyraminx on the side table.
I turned away when Hyein noticed me staring at a Pyraminx on the side table.
"So, senpai, why'd you join the Mystery Club?" she asked. "You don't seem like the type."
I picked up the tetrahedral puzzle. "Didn't get much choice."
She smiled. "You solved the cipher fast. Like it was nothing."
II twisted the pieces. "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 Minji."
She tilted her head. "She's got enemies, right?"
I raised an eyebrow.
"Sorry," she said quickly. "Just curious."
She pulled a small book from the shelf. "You remind me of Chaniel."
"The club leader?"
She nodded. "My childhood friend. He was obsessed with puzzles even back then. Went to the UK for six years. Came back last year."
Smart enough to run a puzzle club as a freshman.
"He's the reason I joined," she added. "It's the only place we still hang out."
My attention drifted to a small board game on a side table.
Hyein 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.
"Games like this are mostly memorization, and I'm only good at problem-solving. That's why I'm not in elite section. But less pressure, more time for puzzles like this."
"How will you deal with Collin?" I asked.
She sighed. "I'll shut it down. I just hope it doesn't ruin the club."
I slid my stone forward, setting up the trap.
The door opened.
A tall freshman stepped inside, backpack slung over one shoulder.
Hyein glanced at him. Something flickered across her face.
The board stayed frozen between us.