Jang Do-young is a homicide detective who likes to use violence when dealing with criminals, while Oh Jin-woo is a prosecutor who believes in the importance of data and evidence. After the murder of his younger half-brother, Do-young and Jin-woo meet when Do-young interrupts a stakeout in an attempt at vengeance. The unlikely duo join forces to bring gangster boss Yu Kang-jin to justice, but find that he is too well connected. Being unsuccessful in bringing Yu Kang-jin to justice the duo turn to violence in order to bring him down.