The library had never been my battlefield.
Too quiet. Too serious. Too… carpet-scented.
But today, I was hunting old theater records—specifically a blueprint of the 2nd-year cultural festival stage layout from three years ago. Why? Because something was still bugging me about that blueprint switch last week.
My detective senses were tingling. Or maybe I just had nothing better to do while Koharu was off practicing lines with Riku again.
"Looking for the 2-B archives?" a soft voice asked.
I turned, nearly bumping into someone I hadn't noticed.
A girl. Thin, pale, neat shoulder-length hair, glasses with silver frames, and an expression like she was always calculating three moves ahead. Her uniform was perfectly pressed, and she clutched a puzzle cube like it was her stress toy of choice.
"I, uh, yeah," I said. "How'd you know?"
"You've opened four drawers and checked the wrong section twice. You're methodical but distracted. Classic signs of inefficient pattern recognition."
I blinked.
"I'm Mitsuki Shiranui," she said. "Puzzle Research Club."
"That's a real club?"
"Not exactly. I'm the only member."
"…Figures."
She turned on her heel and walked two aisles down, then pulled a dusty folder from the shelf like she had x-ray vision.
"You want this."
She handed it to me.
I opened it. Boom. There was the exact blueprint I needed.
"…How?"
"I memorize the layout of every file I read. It's relaxing."
"You're scary."
"Thank you."
We sat down at a side table. I started scanning the pages. Mitsuki didn't move—just stared at me over her cube.
"You're the 'NPC lead,' right?" she said.
I froze. "You've heard of that?"
"I observe all school patterns. Koharu Minami disrupts every one. You're her current focus."
"She's more like a natural disaster."
"She likes you."
I coughed. "Uh, that's—what?"
"I tested her last week. Left a note on her desk saying you'd transferred schools. She panicked, ran to the office, and kicked over a recycling bin."
"That… actually happened?"
She nodded. "Then I ate lunch with you."
"You what now?"
"I'm doing it now," she said plainly, placing a boxed sandwich beside mine. "Testing variables. You're surprisingly interesting."
"…In a test-subject kind of way?"
She ignored that and pulled out a folded paper.
"A riddle," she said. "To confirm my hypothesis."
"You carry around riddles?"
"Of course."
She slid it to me.
> "I speak without a mouth,
I hear without ears.
I have no body,
But I come alive with wind.
What am I?"
I grinned. "An echo."
Her eyes widened slightly.
"That was fast."
"I like puzzles too," I shrugged.
"I see," she murmured. "A natural decoder. Like a cheat code disguised as background character."
She folded the paper back up, then did something alarming: she smiled.
A tiny one. Barely there.
But it was a smile.
---
The next day, Mitsuki sat next to me again during lunch. Wordlessly.
The day after that, she followed me into the prop room, adjusted the light gel angles "for symmetry," and then sat reading a book while I worked.
By Thursday, she'd begun calling me "Senpai." I had no idea why.
Meanwhile…
---
"Who. Is. She?"
Koharu was glaring from behind a costume rack like a pissed-off cat in a maid dress.
"Huh?" I blinked, midway through taping a fake window to a backdrop.
"Library girl. Megane-chan. Puzzle gremlin. Whatever her name is."
"You mean Mitsuki?"
"Oh, Mitsuki, is it now?" she said, crossing her arms. "Didn't know you were into human calculators."
"She's just curious. Gave me a riddle."
"You fall for girls who give you riddles now?! Should I start speaking in haikus?!"
"I didn't fall—she just started hanging around."
"Like a fungus."
"She's actually pretty nice."
Koharu narrowed her eyes. "You're blushing."
"I'm not."
"You're totally blushing. Right cheek, lower edge."
"You've mapped my blush zones?!"
She stomped over and poked my forehead. "Don't make me get jealous, NPC-kun."
"I didn't do anything!"
"You solved her stupid riddle and now she wants to reproduce with you or whatever puzzle girls do!"
"Are you—are you jealous for real?!"
"I—!" she sputtered. "No! I'm just—territorial!"
I raised an eyebrow.
"Okay, maybe I am a little jealous!" she exploded. "But only because we're in the middle of our arc and now you're flirting with side quests!"
I laughed. "You're so dramatic."
She pouted. "You were supposed to be my dumb NPC."
"…Well, maybe I got patched."
She blinked.
"Bug fix complete," I added.
"You're unbelievable," she muttered, punching my shoulder.
---
Later that day, I passed Mitsuki in the hallway.
She handed me a folded paper without a word and kept walking.
I opened it.
> "Two are in love.
One sees the world as patterns.
The other sees it as stories.
What do you see?"
I stared at the question.
Then I looked up, where both girls had disappeared down opposite sides of the hallway.
And for the first time, I wondered if I really was the NPC…
…or if I'd just been waiting for someone to start the game.
---
To be continued