To combat rising violent crimes, the Police Chief asks Detective Oh Goo-Tak (Kim Sang-Joong) to form a team consisting of criminals. Detective Oh Goo-Tak is currently suspended from the police force for using excessive force. Detective Oh Goo-Tak gathers team members: Park Woong-Cheol (Ma Dong-Seok) who is a gangster, Lee Jung-Moon (Park Hae-Jin) who is the youngest serial killer with extraordinary intelligence and Jung Tae-Soo (Jo Dong-Hyeok) who is a contract killer. Also, Police Inspector Yoo Mi-Young (Gang Ye-Won) joins the team. She tries to have the guys work as a team by dealing with them rationally and sometimes emotionally.