 In Seoul, parts not matching of severed copses of three men are found in cars and bags left in public spaces. Detective Cho, who is under investigation of the Internal Affairs, is assigned to lead the investigation with his team. When the identities of the men are discovered, the police finds that the artist Su-Yeon Chae, who lives with her friend Seungmin Oh, had been lover of the men. Detective Cho and his force protect Su-Yeon and follows the leads based one the information she tells, while the killer executes other victims. However, Cho discloses very dark secrets in the end, finding the real motives of the murderer.