People always said Yoon Serin was sweet.

  She helped her teachers, smiled at the lunch dies, even stayed behind after css to stack chairs. The kind of girl who received quiet praises and polite affection.

  It was easy.

  All she had to do was copy the right expressions. Smile when they smiled. Tilt her head just so. Lower her voice to a soothing tone.

  None of it was real.

  Underneath the sweetness, there was nothing but noise. Endless, shrieking boredom. The same routine. The same faces. The same humans pretending to be kind when they were all disgusting beneath the surface.

  Until one of them crossed a line.

  The girl from her department. Lee Ahrin.

  Too loud. Too self-important. Too clingy. She called Serin her "bestie" without permission. She touched her hair. She borrowed her lip gloss without asking.

  And today, she posted a group photo—cropped so that Serin’s face was half cut out.

  That was enough.

  Serin sat on her neatly made bed, legs crossed, a sheet mask clinging to her perfect skin as she scrolled through her phone. She stared at Ahrin’s post for exactly six seconds.

  Then she opened a different app—a notes file.

  [Target: Lee Ahrin]

  Annoyance: 6/10

  Last Straw: Cropping my face

  Time of death: TBD

  Her lips curled.

  “I think I’ll make it look like an accident,” she murmured to herself. “Maybe a te-night slip on the stairs. Or an allergic reaction. She’s been drinking soy milk tely…”

  She turned her head to the side, considering the options, tapping her fingernail against her phone.

  But then—his face appeared in her mind.

  Han Sihun.

  So strange. So sharp. And worst of all… so fun.

  She hadn’t had someone look at her like that in years. Like he knew. Like he sensed something wasn’t right but couldn’t prove it.

  It made her stomach twist. Not in fear. In excitement.

  What if she left a clue this time?

  A tiny one. Not enough to get caught, but enough to draw him closer.

  A trail of breadcrumbs for the genius to follow.

  ---

  The next day, the campus was buzzing. A girl had fainted in the dining hall after eating her yogurt parfait—anaphyxis. But the EpiPen had been faulty. She was fine now, but the incident had people whispering.

  And Serin?

  Serin stood in the courtyard, calmly sipping iced coffee as if the world had nothing to do with her.

  Han Sihun arrived twenty minutes ter. He was wearing a grey coat over his turtleneck today, hair slightly tousled. His eyes scanned the scene like a lion in a zoo—bored, detached, powerful.

  Their eyes met again.

  And this time, he walked straight up to her.

  “You were here?” he asked.

  Serin looked up from her coffee. “Mm. The yogurt looked suspicious, so I didn’t eat.”

  Sihun stared at her.

  Then said, “You’re either very lucky. Or very calcuting.”

  She smiled. “I’ll let you decide.”

  “Already decided.”

  “Oh?”

  He stepped closer, lowering his voice so only she could hear.

  “You like games.”

  “And you like pying hero,” she replied sweetly.

  A beat passed between them—charged, heavy, thrilling.

  Then she tilted her head, brushing imaginary dust off his coat.

  “Dr. Han,” she said softly, “what would you do if you fell in love with a killer?”

  He didn’t blink.

  “I’d perform her autopsy myself,” he murmured.

  Serin ughed quietly.

  God, she thought. He really might be the one.