A convicted thief in Dartmoor prison hides the location of the stolen Bank of England printing plates inside three music boxes. When the innocent purchasers of the boxes start to be murdered, Holmes and Watson investigate.
A series of fourteen films based on Sir Arthur Conan Doyle's Sherlock Holmes stories was released between 1939 and 1946; the British actors Basil Rathbone and Nigel Bruce played Holmes and Dr. John Watson, respectively. The first two films in the series were produced by 20th Century Fox and released in 1939. The studio stopped making the films after these, but Universal Pictures acquired the rights from the Doyle estate and produced a further twelve films. Although the films from 20th Century Fox had large budgets, high production values, and were set in the Victorian era, Universal updated the films to the contemporary era of the Second World War, and produced them as B pictures with lower budgets. Both Rathbone and Bruce continued their roles when the series changed studios, as did Mary Gordon, who played the recurring character, Mrs. Hudson.
