Successive murders show that a vicious and cold-blooded serial killer lurks in this rainy city, and that this person is most likely to be local.

Yu Guowei (Duan Yihong) is a director of the Factory Security Division.

He was called "Yu Shen Tan" because he has repeatedly cracked the theft cases in the factory.

After the murder, Yu Guowei felt that he had the responsibility to contribute to investigating the truth of the case.

Yu Guowei decided to use his own strength to investigate the truth of the case and met a woman named Yan Zi (Jiang Yiyan) in an accident.