Sherlock Holmes investigates when young women around London turn up murdered, each with a finger severed. Scotland Yard suspects a madman, but Holmes believes the killings to be part of a diabolical plot.
The Good Comrades are a collection of varied gentlemen who crave one thing - solitude. They reside at Drearcliff House, ancestral home of their eldest member. All seems serene and convivial until one by one the members begin to perish in the most grisly of manners. Foul play is suspected by the Good Comrades' insurance agent, who turns to Sherlock Holmes and Dr. John Watson for guidance.
Mortimer Brewster, a newspaper drama critic, playwright, and author known for his diatribes against marriage, suddenly falls in love and gets married; but when he makes a quick trip home to tell his two maiden aunts, he finds out his aunts' hobby - killing lonely old men and burying them in the cellar!
The famous Borgia Pearl, a valuable gem with a history of bringing murder and misfortune to its owner since the days of the Borgias, is brought to London, thanks in part to Sherlock Holmes. But before long the jewel is stolen, due to an error on Holmes' part, and shortly thereafter, a series of horrible murders begin, the murderer leaving his victims with their spines snapped and surrounded by a mass of smashed china.
When a woman is found dead with her throat torn out, the local villagers blame a supernatural monster. But Sherlock Holmes, who gets drawn into the case from nearby Quebec, suspects a human murderer.
Sherlock Holmes investigates a series of so-called "pajama suicides". He knows the female villain behind them is as cunning as Moriarty and as venomous as a spider. Based on "The Sign of Four" and the short stories "The Dying Detective", "The Final Problem", "The Speckled Band" and "The Adventure of the Devil's Foot".
During WWII several murders occur at a convalescent home where Dr. Watson has volunteered his services. He summons Holmes for help and the master detective proceeds to solve the crime from a long list of suspects including the owners of the home, the staff and the patients recovering there.
In World War II, a British secret agent carrying a vitally important document is kidnapped en route to Washington. The British government calls on Sherlock Holmes to recover it.