So "Charlie" (Warner Oland) is to be the guest of honour at a grand banquet. That's all going fine until a prominent British diplomat "Sir Stanley" (David Torrence) finds that his planned gift to our honourable detective is quite lethal... Together with No. 1 son "Lee" (Keye Luke) they must discover whether it was he, or the diplomat, who was the target of their assailant. It doesn't take them long before they, together with local police commissioner "Col. Watkins" (Halliwell Hobbes) and an American agent "Andrews" (Russell Hicks) stumble upon an opium smuggling caper that might just involve the handsome fiancée "Nash" (Jon Hall) of the murdered man's daughter "Diana" (Irene Hervey). Still with me? Well, it's worth paying attention as the story is one of the better efforts and there are quite a few clues to be had as the threads come together. Plenty of quickly-paced banter between father and the constantly (amorously) preoccupied son, and even a rather gentle ditty about "Fu Manchu" from the star help this amiable drama log nicely.