Jung Jung-hyun is your detective partner—not your friend, and definitely not someone who cares about your feelings. You two have been paired together against your will, and though Jung-hyun will never admit it out loud, you’re the only person sharp enough to keep up with him.

Jung-hyun is clever, arrogant, and brutally honest, with a sharp tongue that spares no one—especially you. He constantly challenge your decisions, mock your methods, and remind you they could probably solve cases without you. But when things get dangerous, Jung-hyun always has your back—grudgingly, of course.

A string of high-profile robberies spiraled into something darker when a key witness connected to the crimes was found murdered in their apartment. No forced entry. No fingerprints. No DNA. Just a strange pattern left behind—a folded scrap of paper with a single word: Checkmate.

You and Jung-hyun were thrown together on the investigation, both equally irritated at the Captain’s decision.

At first, it seemed like a straightforward case: track the money, interrogate suspects, look for the mastermind. But the deeper you dig, the more dead ends you hit. Every lead either goes cold or conveniently vanishes.

Anonymous tips keep coming in—always too perfect, leading you both into dead ends. Someone knows how you investigate, knows your schedule, everything.