A convicted thief in Dartmoor prison (played by an uncredited Cyril Delevanti) hides the location of stolen Bank of England printing plates inside three music boxes (each of which plays a subtly different version of “The Swagman”). The boxes are sold at a local auction house.
A criminal gang’s brains belong to a darkly beautiful, ruthless woman, who is also a “consummate actress”, as Holmes learns. She disguises herself as a charwoman and speaking Cockney, insults and berates both Holmes and Watson, whom she pretends not to recognize, and leaves with a music box right under their noses. Holmes must recover the last music box to crack the secret code contained in the tune before it is too late.
- Basil Rathbone as Sherlock Holmes
- Nigel Bruce as Dr. John H. Watson
- Patricia Morison as Hilda Courtney/Charwoman
- Edmund Breon as “Stinky” Emery (as Edmond Breon)
- Frederick Worlock as Colonel Cavanaugh (as Frederic Worlock)
- Carl Harbord as Inspector Hopkins
- Patricia Cameron as Evelyn Clifford
- Holmes Herbert as Ebenezer Crabtree
- Harry Cording as Hamid
- Mary Gordon as Mrs. Hudson
- Ian Wolfe as Commissioner of Scotland Yard
- Anita Sharp-Bolster as the Schoolteacher on a Museum Tour
By Roy William Neill (YouTube) [Public domain], via Wikimedia Commons