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.

• Universal Pictures
• Basil Rathbone
• Nigel Bruce
• Patricia Morison
• Frederick Worlock
• Harry Cording
• Carl Harbord
• Holmes Herbert
• Edmund Breon