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
Sherlock Holmes
Nigel Bruce
Dr. John H. Watson
Patricia Morison
Mrs. Hilda Courtney
Frederick Worlock
Colonel Cavanaugh
Harry Cording
Hamid
Carl Harbord
Inspector Hopkins
Holmes Herbert
Ebenezer Crabtree
Edmund Breon
Julian 'Stinky' Emery
