This drama follows Jung Ba Reum (Lee Seung Gi),a steadfast police officer, whose life changes when he encounters a psychopathic serial killer. This drives him and his partner Go Moo Chi (Lee Hee Joon)to unearth the truth behind psychopathic behaviours. This also raises the questions, whether it is possible to scan a psychopath in the mother’s womb using fetal genetic testing? And if the child in the womb is a psychopath, will it be wise to have that child?