A card cheat is threatened with exposure into joining a criminal enterprise that Sherlock Holmes believes is controlled by Professor Moriarity.

Holmes goes on the trail of a Rembrandt painting, stolen by a drug-addicted artist.

A young woman turns to Holmes for protection when she's menaced by an escaped killer seeking missing treasure. However, when the woman is kidnapped, Holmes and Watson must penetrate the city's criminal underworld to find her.

Holmes, retired to Sussex, is drawn into a last case when his arch enemy Moriarty arranges with an American gang to kill one John Douglas, a country gentleman with a mysterious past. Holmes' methods baffle Watson and Lestrade, but his results astonish them. In a long flashback, the victim's wife tells the story of the sinister Vermissa Valley.

Holmes takes a vacation and visits his old friend Sir Henry Baskerville. His vacation ends when he suddenly finds himself in the middle of a double-murder mystery. Now he's got to find Professor Moriarty and the horse Silver Blaze before the great cup final horse race.