University professor George Kingsley is struck by gangsters while crossing the street, leaving him with brain damage and one of the gangsters, Cannon, paralyzed. Kingsley's friend Dr. Sovac attends to both men, and when Cannon offers him a reward for aiding his recovery, Kovac transplants part of Cannon's brain into the dying Kingsley's skull, creating a dual personality.

When news reporter Walter Garrett arrives at the hotel room of bombshell actress Angela Merrova to conduct an interview, he finds her dead from multiple stab wounds. He returns with the police to find the hotel empty and the body vanished. Garrett writes about the incident but is fired when Merrova, alive and well, goes to the paper to complain. Now his only chance to get his job back is to find the truth, which involves the grisly scheme of a madman.

Detective James Lee Wong must find the "Eye of the Daughter of the Moon," a priceless but cursed sapphire stolen in China and smuggled to America. His search takes him into the heart of Chinatown and to the dreaded "House of Hate" to find the deadly gem before it can kill again.

After being mistaken for Scotland Yard detectives, two vaudevillians (Michael Whalen, Chick Chandler) try to solve a murder in a Midwestern town.

On his uncle's death Sir Henry Baskerville returns from Canada to take charge of his ancestral hall on the desolate moors of Devonshire, and finds that Sherlock Holmes is there to investigate the local belief that his uncle was killed by a monster hound that has roamed the moors since 1650, and is likely to strike again at Sir Henry.

When an escaped circus gorilla appears to have gone on a murderous rampage, a threatened attorney calls on the detective trio of Garrity, Harrigan and Mullivan to act as bodyguards. In short order, we discover that there is more to the attorney than meets the eye, and the ape may be innocent after all. When a pretty young heiress faces peril, it's up to our heroic trio to save the day.

Ten years after the death of millionaire Cyrus Norman, his will is to be read out to his six relatives, including Joyce Norman and Wally Campbell. Organized by Norman's lawyer, Crosby, the six meet at Norman's eerie New Orleans Gothic mansion. During the reading, the superstitious housekeeper declares that someone will be dead by midnight. Wally fears for Joyce when she is declared the sole inheritor, but all are alarmed when Crosby turns up dead.

A Scotland Yard inspector and his reporter friend arrive on vacation in a small village and are immediately involved in what is claimed to be a murder but the body has disappeared, leaving it to the inspector to find the body, determine the motive and find the killer.

Having once again avoided criminal conviction, Professor Moriarity develops a murderous plan to “finish off” his last major nemesis, Sherlock Holmes, by making him fail to prevent the perfect crime. Does it involve a family curse, the crown jewels of England, or something else…

In England, an eccentric police inspector, an earnest test pilot and a spunky female reporter team up to solve the mystery of a series of test aircraft which have disappeared without a trace while over the ocean on their maiden flights; unaware, as they are, that a spy ring has been shooting the planes down with a ray machine hidden aboard a salvage vessel which is on hand to haul the downed aircraft aboard, crews and all.

To try solving the strange disappearances of 11 young Parisian women, the police obtain the services of Adrienne Charpentier, friend of the latest missing person.

Detective Nick Carter is brought in to foil spies at the Radex Airplane Factory, where a new fighter plane is under manufacture.

When a close friend of the Drew family is accused of murder in a rural community, Nancy, aided by boyfriend Ted, helps her lawyer father expose the real killers.

While participating in a contest at a local newspaper in which school children are asked to submit a news story, local attorney Carson Drew's daughter Nancy intercepts a real story assignment. She "covers" the inquest of the death of a woman who was poisoned. Nancy doesn't think the young woman accused of the crime is guilty and corrals her neighbor Ted into searching for a vital piece of evidence and stumbles onto the identity of the real killer.

Nancy helps two aging spinsters fulfill the byzantine provisions of their father's will, but the murder of their chauffeur complicates matters.

A pretty Chinese woman, seeking help from San Francisco detective James Lee Wong, is killed by a poisoned dart in his front hall, having time only to scrawl "Captain J" on a sheet of paper. She proves to be Princess Lin Hwa, on a secret military mission for Chinese forces fighting the Japanese invasion. Mr. Wong finds two captains with the intial J in the case, neither being quite what he seems; there's fog on the waterfront and someone still has that poison-dart gun...

A Japanese man claiming to be Mr. Moto, of the International Police, is abducted and murdered soon after disembarking from a ship at Port Said in Egypt. The real Mr. Moto is already in Port Said, investigating a conspiracy against the British and French governments.

A maker of illusions for magicians protects an ingenue likely to be murdered.

A nightclub singer refuses to "date" customers, so she's framed for the murder of her aunt.

Detective Guy Johnson's client, Willie Heywood, is framed for murder. While Guy hides him so he can catch the real killer, both of them are nabbed by the police, tried, convicted and sentenced to jail: Guy for a year with Willie to be executed. On the way to jail, Guy comes across a clue and escapes from the police.

A Chinese general's daughter tracks her father to a slave-labor tyrant's jungle empire.

The Sloanes tie murder to the theft of a Shakespeare manuscript.

A mad doctor named Zanoff uses a drug to bring himself back from the dead after his execution in prison. Dick Tracy sets out to capture Zanoff before he can put his criminal gang back together again.

Chan, in Paris for a reunion with friends from World War I, becomes involved in investigating the murder of a munitions manufacturer who was supplying arms to the enemy, even as the rising clouds of World War II force the city into nightly blackout status..