Homicide detective Jung Jae-gon (Kim Nam-gil) is chasing after a suspect of a murder case (Park Sung-woong). He knew his suspect would get in touch with his lover Kim Hye-kyung (Jeon Do-yeon), a madam at a third-rate bar. Jung goes undercover as the suspect's former cellmate and becomes the floor manager at the bar where Kim works, and watches her every move.