Detective Han, who for years has been secretly doing dirty work for the corrupt mayor Park Sungbae, is now pressured by a ruthless prosecutor Kim Cha-in to cooperate in an investigation against the mayor. Feeling trapped, Han persuades his young partner Sunmo 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 this dog-eat-dog world.