Homicide detective Oh Jeong Su (Kam Woo Seong) is investigating a series of brutal murders that occured without valid reason, where all the victims are females. Together with fellow detective So Young (Jang Sin Yeong) they decide to track down the killer which is still on the loose. During the process he meets with Ji Hyun (Lee Seung Min), the only female surviving victim who has been badly traumatised from previous incident and soon falls in love with her. As their love grow, more misfortune are facing them and for the sake of revenge Oh decides to deal with the killer outside the law.