Detectives Oh Goo Tak (Kim Sang Joong) and Yoo Mi Young (Kang Ye Won) rally up a team of criminals to catch other criminals. Their team includes serial killer psychopath Lee Jung Moon (Park Hae Jin), contract killer Jung Tae Soo (Jo Dong Hyuk), and mob boss Park Woong Chul (Ma Dong Suk).
The team is called upon when there is a major homicide case. However, the key mystery of the series is revolving around Jung Moon as he is believed to be the serial killer who has killed Oh Goo Tak's daughter. But Oh Goo Tak has doubts and puts this team together. Is Jung Moon really the killer everyone believes him to be?
The team starts to discover forgiveness and the hope of starting anew.