Tae-su (Kim Sang-kyung), a policeman who lost his sister in a serial murder case, was lurking on a rainy night to investigate a hit-and-run case. He accidentally caught the serial killer suspect Kang Chuan (Park Seong-woong), and the tragedy began. Tae-su accidentally learned that Kang Chuan was the murderer of his sister. In order to find his sister's body, Tae-su actually knelt down... While identifying the scene, another man who lost his beloved wife, Seong-hyun (Kim Sung-kyun), appeared in grief and anger...