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. Basil Rathbone, Nigel Bruce, Patricia Morison, Frederick Worlock, Harry Cording, Carl Harbord, Holmes Herbert Added on Amazon Prime 2023-02-05. Added on Starz 2022-05-14.