Sherlock Holmes and Watson are on the trail of a criminal and scientific mastermind who seems to control monsters and creations which defy belief.
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.
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 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.
Sherlock Holmes is drawn into the case of Jack the Ripper, who is killing prostitutes in London's East End. Assisted by Dr. Watson, and using information provided by a renowned psychic, Robert Lees, Holmes finds that the murders may have their roots in a Royal indiscretion and that a cover-up is being managed by politicians at the highest level, all of whom happen to be Masons.
Holmes and Dr. Watson take on the case of a beautiful woman whose husband has vanished. The investigation proves strange indeed, involving six missing midgets, villainous monks, a Scottish castle, the Loch Ness monster, and covert naval experiments.
When a nobleman is threatened by a family curse on his newly inherited estate, detective Sherlock Holmes is hired to investigate.
Two dubious characters disguise themselves as Holmes and Watson to gain attention and end up chasing counterfeiters and stolen stamps.
After the death of his wife, wealthy retiree Justin Playfair creates a fantasy world for himself in which he is the legendary detective Sherlock Holmes, even dressing like the character. Out of concern for Justin's money more than his health, his brother Blevins puts him under the care of psychiatrist Dr. Mildred Watson. As Dr. Watson grows fond of Justin, she begins to play along with his theories, eventually becoming an assistant in his investigations.
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.