Detective Han has for years been secretly doing dirty work for the corrupt mayor Park Sung-Bae. However, when an investigation is raised against the mayor, Detective Han is pressured by a ruthless prosecutor Kim Cha-In to cooperate. Feeling trapped, Han persuades his young partner Sun-Mo to take over his work for the mayor, but things start to get tangled in unpredictable ways. As things are getting worse, only the most evil survives in the dark and dangerous underworld.