Sandra Carpenter is a London-based dancer who is distraught to learn that her friend has disappeared. Soon after the disappearance, she's approached by Harley Temple, a police investigator who believes her friend has been murdered by a serial killer who uses personal ads to find his victims. Temple hatches a plan to catch the killer using Sandra as bait, and Sandra agrees to help.
Up-and-coming Hollywood actor/crooner, Vic Morton, has a secret. He starts receiving death threats in the mail and an attempt on his life is made. Soon after, two of his associates are murdered. Who is behind it all?
The dream is unusually vivid: Bank employee Vince Grayson finds himself murdering a man in a sinister octagonal-shaped room lined with mirrors while a mysterious woman breaks into a safe. It is so vivid that Vince suspects it may have really happened. To get the dream off his mind, he goes on a picnic with some relatives. When a thunderstorm forces his party into a nearby mansion, Vince discovers that the bizarre room does exist, and it means nothing but trouble.
Ronnie Jackson is a lowly baby photographer who secretly fantasizes about being a private detective. When a lovely baroness actually mistakes him for one and asks him to help locate her missing husband, Baron Montay, Ronnie finds himself agreeing. Several days later he is on death row whiling away the hours until his execution by recounting to a group of reporters the bizarre tale of how he ended up there.
A woman is married to the son of a doctor, the proprietor of a private sanatorium, where she is under unwilling treatment. Both the son and the doctor indicate they want the marriage dissolved. Arriving at the scene is a mysterious personage identified as the doctor's cousin who formerly was a stage magician in Europe. He is accompanied by a threatening dwarf.
After three men are convicted of bank robberies, Charlie becomes suspicious. After some investigation Charlie finds the men are innocent and that the fingerprint evidence used to convict them had been forged. Charlie then proceeds to find the true bank robbers.
A convicted thief in Dartmoor prison hides the location of the stolen Bank of England printing plates inside three music boxes. When the innocent purchasers of the boxes start to be murdered, Holmes and Watson investigate.
Holmes and Watson board a passenger train bound from London to Edinburgh, to guard the Star of Rhodesia, an enormous diamond worth a fortune belonging to an elderly woman of wealth; but within the first hour of the trip, the woman's son is murdered and the diamond stolen and any of the passengers in their car could be the killer thief.
Ten strangers are summoned to a remote island and while they are waiting for the mysterious host to appear, a recording levels serious accusations at each of the guests. Soon they start being murdered, one by one. As the survivors try to keep their wits, they reach a disturbing conclusion: one of them must be the killer.
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.
A feud between rival newspapermen Kruger (Bromberg) and McDonald (Guilfoyle) goes deadly when blackmailing McDonald ends up murdered and his corpse planted in the trunk of Kruger's car. Good guy Kruger attempts to hide McDonald's body, with the help of chauffeur Hogan (Jenks), to keep from being charged with murder. However, zany scenarios occur as the body just won't stay hidden, and keeps on popping up in multiple places where Kruger is located, leading to him hiding the body again and again while Kruger tries to find the real killer.
Leo, a former convict, is living in seclusion on an island with his step-daughter, the daughter of his late wife. Leo was framed by a group of former business associates, and he also suspects that one of them killed his wife. He has invited the group to his island, tempting them by hinting about a hidden fortune, and he has installed a number of traps and secret passages in his home. He is aided in his efforts by a former cell-mate who holds a grudge against the same persons. When everyone arrives, the atmosphere of mutual suspicion and the thick fog that covers the island promise a tense and hazardous weekend for everyone.