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.
Acting
Rathbone's razor-sharp Holmes vs. Morison's ice-queen villain.
Direction
Neill's shadow-drenched finale at Garrideb house.
Writing
Watson's bumbling actually advances the plot for once.

Director
Roy William Neill
Trivia, insights & behind the scenes
This was the last of fourteen Rathbone/Bruce Holmes films; Universal killed the series despite solid profits.
Mrs. Courtney was rare female mastermind for 1946—Holmes creators later admitted she scared censors more than Moriarty ever did.