In the cold winter of 2001, a murder case occurred in the affiliated hospital of a printing factory in Haizhou City. Rookie policeman Leng Xiaobing and his senior rushed to the scene after receiving a report, but accidentally faced the murderer of the serial murder in Haizhou City. Leng Xiaobing was timid and afraid to shoot. The murderer fled from the scene and killed his senior, Li Lan. Another witness at the scene is a victim, orphan Xia Mu, hiding under the bed. In order to stay in the police force, Leng Xiaobing concealed the fact that he did not dare to shoot, Xia Mu did not expose him either. So far, the murderer has been in the hiding, and the Haizhou case is still pending.

Sixteen years later, Xia Mu came to the force for an internship. Threatening with the fact that Leng Xiaobing didn't dare to shoot, she coerce him into investigating the case with her. Just as the two pointed their suspicions at the father of the psychologist Shen Yu, Shen Yu also launched a plan to create a crime of imitation. Then a corpse that had been dead for more than sixteen years caused the three of them to fall into the dark night of souls. The three finally joined forces to trap the real murderer.