Basil Rathbone stars as Sherlock Holmes, who goes head-to-head against his archenemy, Professor Moriarty (George Zucco), who's planning to steal the Star of Delhi gem from the Crown Jewels in this classic Hollywood thriller. To keep the intrepid detective from figuring out his main caper, Moriarty sends anonymous threatening messages to an affluent woman who enlists Holmes's help. Can Holmes and Dr. Watson (Nigel Bruce) put a stop to both crimes?