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.
Scion of the once-rich Mitchell family, Herbert Wynn is found shot to death. Nurse Adams, bored by hospital routine, is recruited by the police to ferret out clues as she tends to Wynn's elderly aunt Julia. Jokingly given the 'rank' of Miss Pinkerton, after the famous detective agency, Adams probes into the mystery, but not before a second death.
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.
Margaret Holt and her brother Victor set out to smash a narcotics ring responsible for their father's death. Young reporter John Howell and eccentric mystery writer Winthrop Clavering help unravel the truth about the murder.
The boys think their days of fishing to feed themselves have come to an end, when Stan's rich uncle Ebenezer dies leaving a large estate. But they soon learn that Ebenezer was murdered and all the relatives, including Stan, are suspects.
London. A mysterious serial killer brutally murders young blond women by stalking them in the night fog. One foggy, sinister night, a young man who claims his name is Jonathan Drew arrives at the guest house run by the Bunting family and rents a room.
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.
When a couple of scammers hold young Alice Faulkner against her will to discover the whereabouts of letters whose dissemination could cause a scandal affecting the royal family, Sherlock Holmes decides to take over the case. (Considered lost, a copy was found in 2014, in the vaults of the Cinémathèque Française.)