In his past, Byeong-Soo was a serial killer. He now suffers from Alzheimer’s. He lives with his adult daughter Eun-Hee. One day, he remembers that a man he got into a car accident with is also a killer. That man is Min Tae-Joo. Meanwhile, Min Tae-Joo begins to woo Byeong-Soo’s daughter. To protect his daughter, Byeong-Soo struggles to retain his memory and to kill Tae-Joo.