A serial murderer in the city has shaken the people of old Shanghai and a trio of investigators join hands to solve the mystery. As he was investigating a case, private detective Chen Yiming (Wang Longzheng) crosses paths with Zhang Tianxiao (Ji Ning), the police director's son and Yao Fei (Gan Lu), a beautiful woman who has returned from abroad. They come to form a three-man team determined to crack the case.