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.
A mining engineer teams up with a crusty deputy sheriff to solve the mystery killings at an old mine where the owner's family waits for him to die, and where a valuable radium strike may have been made.
Hard-boiled newspaper reporter Larry Doyle (Robert Armstrong) goes a bit too far in celebrating a work bonus and wakes up on a train bound for St. Louis with only a buck on his person. To remedy the problem, Doyle pawns the revolver he's carrying. When the gun is subsequently used in a murder, Doyle's problems only multiply. In the meantime, he's also fallen in love with a comely stranger (Maxine Doyle) he convinced to impersonate his wife.
A ghostly and deadly dinner party, which at first turns out to be an elaborate staging of a new play for the benefit of a Broadway producer, becomes a true mystery when the players start to go missing.
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.
The owner of a large mansion in the country throws a costume party for some of his friends. However, the party turns sour when he is found stabbed to death in a closet. The police and a guest try to discover who committed the murder.
Philo Vance, accompanied by his prize-losing Scottish terrier, investigates the locked-room murder of a prominent and much-hated collector whose broken Chinese vase provides an important clue.
Rival newspaper reporters Pat Morgan and Ted Rand find themselves unraveling the mystery behind the death of a millionaire philanthropist who fell from his penthouse balcony. When it is discovered that the plunge was not an accident, the building's residents come under suspicion. Soon, the body count begins to mount as three more murders occur by strangulation.
A man known to be a mute is suspected of committing a murder, as he was noticed at the scene. However, witnesses saw and heard him talking as he was leaving the scene of the crime. The police must determine if he is the actual killer or if he is being framed.
In London, a secret society led by lawyer Thaddeus Merrydew collects the assets of any of its deceased members and divides them among the remaining members. Society members start dropping like flies. Sherlock Holmes is approached by member James Murphy's widow, who is miffed at being left penniless by her husband. When Captain Pyke is shot, Holmes keys in on his mysterious Chinese widow as well as the shady Merrydew. Other members keep dying: Malcom Dearing first, then Mr. Baker. There is also an attempt on the life of young Eileen Forrester, who became a reluctant society member upon the death of her father. Holmes' uncanny observations and insights are put to the test.
A handsome radio singer has it all--fame, money, adoring fans--but what no one knows is that his accompanist, a hunchbacked piano player, is actually the voice behind the arrogant, abusive "singer"'s fame. The two men fall for the same girl, and when the singer turns up dead, suspicion falls upon his assistant and the girl.
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.
The Wrecker wrecks trains on the L & R Railroad. One of his victims is Larry Baker's father. Baker wants to find the evildoer, among a host of suspects, but it will be difficult since the Wrecker can disguise himself to look like almost anyone
Ruth Earlton has come home to her ancestral mansion to claim her inheritance. Accompanied by her boyfriend, she discovers that her father died suddenly under suspicious circumstances. Now it's her turn, as her deranged and relentless uncle targets her for death with the help of his wife and son, plus a very unhappy ape.
Wealthy Mr. Kennedy shoots his secretary, Channing, during a parlor game, but it turns out the gun was loaded with real bullets. Luckily, criminologist Phillip Montrose is on hand to help the police. When Kennedy quickly ends up dead as well, the police think it's a tidy murder-suicide, but the family lawyer knows of a letter that voiced Kennedy's suspicions about someone who was out to get him. Soon, the cops are on the trail of a ruthless and clever killer who is one step ahead of even Montrose.