A serial murder cases take place. The serial murderer is Jin-Hyeok. Detectives, including Jae-Hwan, try to catch the killer. During their investigation, Jae-Hwan’s very close colleague detective gets killed by Jin-Hyeok. Jae-Hwan chases after Jin-Hyeok and he has a physical struggle with him. When Jae-Hwan wakes up in the hospital room, he realizes that he is in Jin-Hyeok’s body.