Ba Reum finds out about a shocking story behind his brain surgery a year ago. He’s tormented by unwanted memories that keep haunting him. Detective Ko is furious at Han Seo Joon’s remark of being saved and being at peace after accepting Christ and decides to kill him himself.

Ba Reum finds himself acting a lot more violent than before and realizes that it’s getting harder to control himself. He even gets the urge to kill someone. While Ba Reum is terrified that the Yo Han inside him might take him over completely, another murder case occurs that shows the MO of the previous murder cases. If Yo Han wasn’t the culprit of the serial murders, then is the piece of brain transplanted into Ba Reum’s head not of a psychopath?