Detective Jung-soo faces the victims of brutal murders who were killed for no reason and this makes him outraged. During the investigation, he meets Ji-hyun who is the only survivor and marries her, but they cannot escape from her tragic past. One day, Jung-soo's partner, So-young, arrives at the crime scene where she finds Jung-soo crying out in sorrow with his wife and daughter in his arms who are found viciously murdered after they went missing. But as the police and the law let the suspect go because for lack of evidence, Jung-soo decides to take vengeance himself on those unpunished killers and the cruel world.