Vivian Vedder (Renee Godfrey) is transporting her mother's deceased body in it's coffin via train to Scotland. Lady Margaret Carstairs (Mary Forbes) is also aboard the train with her famous Star of Rhodesia diamond. Roland (Geoffrey Steele), Lady Carstair's son, has hired personnel to protect the diamond. Shortly afterward, Roland is murdered and the diamond is stolen. Holmes (Basil Rathbone), is pushed out of the train, nearly to his death, but he climbs back inside and discovers a secret compartment in the coffin carrying Miss Vedder's mother. He suspects that one of the people on the train is the notorious jewel thief, Colonel Sebastian Moran (Alan Mowbray). Miss Vedder admits that a man paid her to transport the coffin. In the luggage compartment, Holmes and Watson find a guard murdered with a poisoned dart. A criminal named Sands (Skelton Knaggs) incapacitates the conductor and steals the diamond, but Moran double-crosses Sands, shooting him dead with the dart gun. The train makes an unexpected stop and a scuffle ensues, but you'll have to watch this classic Holmes mystery to find out how all of this ends. This is vintage Sherlock Holmes material... (57 minutes - 1946 - Black & White - 4:3).