Ding Zhuofei (played by Michael Tse) of the gang "Fok Wo" and Inspector Duan Yifan (played by Pakho Chau) of the anti-triad team are undercover agents planted by both sides in the other camp. Ding Zhuofei has been an undercover agent in "Fok Wo" for ten years. In order to conceal his true identity, he is more ruthless than others, and thus gradually approaches the core. But after torturing his colleagues and watching them die tragically, Ding Zhuofei began to get tired of this endless undercover work... On the other hand, Duan Yifan has been promoted step by step in the anti-triad team and is expected to become the youngest chief inspector. Duan Yifan, who has a happy career and love, began to desire to be a real policeman. He deliberately wanted to get rid of Mr. Song (played by Chan Kai Tai) and the "Tung Lee Trading" behind him... A drug deal between "Fok Wo" and "Tung Lee" turned out to be a scam by the boss of "Fok Wo" to find traitors on both sides. Two policemen, one black and one white, each for their own path of justice, embarked on a life-and-death confrontation...