Actual footage of the 1936 Berlin Olympics is rabbeted into the action of this superior Charlie Chan entry. Assigned by the U.S. Navy to track down a gang of international spies, Charlie Chan (Warner Oland) heads to Berlin, where as luck would have it his son Lee (Keye Luke) is representing the United States as a member of the Olympic swimming team.
Among Lee's teammates is Richard Masters (Allan Lane), who has unfortunately fallen under the spell of the alluring Yvonne Roland (Katherine De Mille), much to the dismay of his sweetheart Betty Adams (Pauline Moore). What no one knows (but Chan suspects) is that Yvonne is one of the spies, in league with the mysterious Arthur Hughes (C. Henry Gordon).
Yvonne hides a stolen secret weapon in Betty's luggage, leading to a not-so-merry chase through Berlin, and the ultimate kidnapping of Lee Chan by the villains. Plus, there's a murder to be solved, and Berlin police chief Strasset (Fredrick Vogeding) isn't about to let Charlie Chan get the credit.
Ironically, Charlie travels from New York to Berlin via the dirigible Hindenburg -- which crashed into flames the same week that Charlie Chan at the Olympics was released (PS: The Nazi swastika on the tail of the airship was matted out by the special-effects crew).