On his return to China, Charlie is honored at a Shanghai banquet for his many accomplishments. Prior to his speech Sir Stanley Woodland, a prominent official in the colony, confides to Charlie that he has discovered some sinister activities and wants to share the information with the detective as soon as they are alone. When Sir Stanley is silenced by a booby-trapped box, Charlie seeks to discover the undivulged secret as well as the killer. Along with Col. Watkins, the police commissioner, and G-Man James Andrews, Charlie works to expose an international opium-smuggling ring operating out of Shanghai. With the help of son Lee, he survives a kidnapping and murder attempt while exposing the identity of the head of the drug ring.