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. However, Chen Yiming discovers that masked behind the series of killings are conspiracies and secrets that relate to his real identity

民国时期的上海，一起脸谱连环杀人案引发城市的混乱，私家侦探陈一鸣卷入其中调查，并因此结识巡捕局长之子张天笑和海归美女姚菲，三人组成侦探团破获此案，陈一鸣却发现案件背后似乎还隐藏着更神秘的阴谋。