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.
While vacationing in St. Moritz, a British couple receive a clue to an imminent assassination attempt, only to learn that their daughter has been kidnapped to keep them quiet.
After the death of a gangster, those familiar with his million dollar stash start mysteriously dying. Police detectives with the help of a clairvoyant try to determine who, living or dead, is responsible.
John Mason returns to the Sally Ann mine to claim his half share. Janet Cater also returns although her father lost his half share to Joe Ryan. Ryan and his gang are also there to get the gold. A mysterious Phantom is also present. Mason's plan to expose Ryan as an outlaw and to force him to turn his share to Janet works. But when distracted by the Phantom, John is made a prisoner by the gang.
When a movie actor is shot and killed during production, the true feelings about the actor begin to surface. As the studio heads worry about negative publicity, one of the writers tags along as the killing is investigated and clues begin to surface.
In 19th century Paris, a maniac abducts young women and injects them with ape blood in an attempt to prove ape-human kinship but constantly meets failure as the abducted women die.
A lovely dame with dangerous lies employs the services of a private detective, who is quickly caught up in the mystery and intrigue of a statuette known as the Maltese Falcon.
When actress Diana Baring is found in a daze beside her colleague’s murdered body, all evidence points to her guilt. During the trial, juror Sir John Menier doubts the verdict, but yields to pressure. Haunted by remorse, he launches his own investigation.
A film projectionist longs to be a detective, and puts his meagre skills to work when he is framed by a rival for stealing his girlfriend's father's pocketwatch.