Han Sihun wasn’t a romantic.

  He didn’t believe in fate, soulmates, or the kind of obsessive yearning people wrote songs about.

  He believed in logic. Anatomy. Chemical processes.

  Love? Love was just a misfiring of neurotransmitters. Lust, a function of scent and symmetry.

  But none of that expined Yoon Serin.

  She shouldn’t have caught his attention. Not truly. On paper, she was ordinary—good grades, clean record, polite background. A cssic honor-student mask.

  But the problem was that he could see the mask.

  That was what unsettled him.

  It wasn’t the way she smiled too easily, it was how mechanical the smile was, like she'd learned it from watching others.

  It wasn’t how she always looked calm, it was how her calmness bordered on bnkness.

  And it wasn’t how she looked at him. It was the tiny flicker behind her eyes... the flicker of recognition.

  She knew he saw her.

  And she liked it.

  ---

  Sihun sat in his private b that night, the room dim except for the spotlight on his newest case file.

  Victim: Lee Ahrin

  Age: 22

  Cause of death: Anaphyctic shock

  Circumstances: Yogurt parfait. EpiPen failed.

  Status: Accident. Officially.

  Unofficially? It didn’t feel right.

  He tapped the eraser of his pencil against his desk. Over and over. The rhythm filled the silence.

  There were no fingerprints on the pen. No traces of poison in the yogurt. No motive.

  Except for one thing: Yoon Serin had been seated directly across from the victim at the time.

  She hadn’t touched her food. She hadn’t even reacted.

  He'd reviewed the security footage four times.

  She was just sitting there... calm, elegant, sipping her drink like nothing was happening.

  While everyone else panicked, she blinked once. Then sipped again.

  Not even a flinch.

  And ter, when he'd asked if she'd been nearby, she hadn’t hesitated. No guilt. No nervous ticks.

  Just that unreadable look of hers.

  What are you, Yoon Serin?

  He stood up and walked to the evidence board.

  On it, he had pinned photos from recent cases—none confirmed homicides. All odd. Too clean. Too convenient.

  All with a single common denominator.

  Her.

  He stared at the pictures, then at the center image—Serin in the courtyard, caught mid-smile by a surveilnce camera.

  Her head tilted just slightly, lips parted, expression soft.

  Beautiful.

  Disturbingly so.

  He’d seen a lot of killers.

  But this one?

  She didn’t fit the mold. No trauma. No rage. No desperation.

  No reason.

  And yet—something inside him thrummed every time he looked at her.

  It wasn’t attraction. Not entirely.

  It was curiosity twisted with danger. Like staring into the sun knowing it could blind you, and still refusing to look away.

  ---

  Later that night, he sat in his apartment, staring at a bnk message on his phone.

  He’d never done this before. Never hovered over a chatbox like some schoolboy.

  “What would you do if you fell in love with a killer?” she had asked.

  He didn’t believe in coincidences.

  But he did believe in temptation.

  And somehow, she’d become his.

  Not his lover.

  His puzzle.