Late 18th-century Joseon dynasty. The King is beleaguered and surrounded by traitors of the ruling elite. They plan to assassinate and replace him with a puppet. But the King has some aces up his sleeve that may help him defeat them all.

Je-In is a mystery novel writer. She chases after a serial killer with her longtime friend Rok-Hwan. Rok-Hwan is a detective. A handsome and mysterious man, Jason, appears in front of them.