

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
Patricia Cameron
Evelyn Clifford

Mary Gordon
Mrs. Hudson