In his past, Byeong-Soo (Sol Kyung-Gu) was a serial killer. He now suffers from Alzheimer’s. Byeong-Soo has a daughter, Eun-Hee (Seol Hyun), but he actually took her from one of his victims. One day, he remembers Eun-Hee's boyfriend (Kim Nam-Gil) approached Eun-Hee to kill her. To protect Eun-Hee, he fights to keep his memory and he plans to kill Tae-Joo.