A young, newly-appointed rookie state trooper, John Shields, is celebrating with his sister Jane, his younger brother Freddie and Tom Marlin, Jane's fiancé and also a trooper, when they hear over the radio that two bandits have just killed a lawyer and his watchman. John and Tom set out in their patrol cars in hopes of capturing the killers, followed by Freddie who hopes some day to qualify as a trooper. Freddie encounters the two two bandits, Spike Doland and Butch and manages to get away with the bag of gold they had stolen. While chasing Freddie they are recognized by John who they kill when he tries to arrest them. Freddie then takes matters into his own hands in seeking to capture the killers of his brother.
Mickey Lofton, young half-brother of famed war-aviator Jerry, fails in his attempt to enter the Canadian Air Corps, because of his fear of thunderstorms developed by an incident in his boyhood days. Jerry, now a Captain in the U.S. Department of Justice, is given an assignment to capture some border oil smugglers. Through his friendship with Raoul McGuire, one of the suspects, Jerry is accepted as a member of the gang. Mickey is in love with Raoul's sister, Molly. Gang leader Moran shoots and wounds Raoul, and is himself shot down by Jerry. Mickey flies Molly and her wounded brother to a hospital. Jerry takes off in another plane to guard Mickey's craft from a pursuing airplane, and crashes his plane into the gangster's plane but parachutes to safety.
A young girl is travelling to London to find work. Arriving at the station, she meets a man who has been stabbed by a member of a gang of crooks involved with greyhound racing. She becomes a suspect, but flees the scene in order to deliver a message to the dead man's brother. She is protected from the police by a night club entertainer, who she learns is the man she is seeking.
A young married couple whose plans for their life together haven't turned out as expected decide to rob the bank where the husband works of $100,000, then hide the money in a safe place and return for it after they serve out their sentences. All goes according to plan until they get out of prison, when they find that they're being trailed by an insurance investigator and the husband's old cellmate, who has decided that he wants a cut of the money.
Drummond's girlfriend is kidnapped by his enemies and he along with his friend Nielsen, an inspector from Scotland Yard, follow the trail and try to rescue her from the kidnappers.
Bob Terry is in love with Lois Borden the daughter of his employer, John Borden. When some bonds are missing from the office, Bob is accused and because of Borden's strong sense of obligation to his stockholders, Bob is railroaded to prison. A few years later, the real thief is apprehended and Bob is released. He now begins his plan for revenge against Borden with the aid of his prison cell mate Todd and a gangster, John Carmody. Soon, some bonds are missing again and Borden knows Bob is involved but because Bob has suffered at his hands before, Borden assumes the responsibility and is about to be sentenced to prison. Todd is shot while trying to steal the bonds back from Carmody, but gets the bonds back to Bob and, before he dies, begs Bob to return them to the owner.
Mary Lou manages to escape abduction by a prostitution ring. She tells the Chief of Detectives they were planning to take her to the Berrywood road house, a well-known den of iniquity. Jim Murray and beautician Belle Harris are using her beauty shop to recruit floozies for their road house circuit. Dona Lee, who works at the beauty salon, is falling in love with young reporter wanna-be Phillip, but Murray gets jealous and makes life rough for him. Meanwhile Dona begins to figure out the racket, but becomes threatened by Murray's unwanted advances.
Holmes takes a vacation and visits his old friend Sir Henry Baskerville. His vacation ends when he suddenly finds himself in the middle of a double-murder mystery. Now he's got to find Professor Moriarty and the horse Silver Blaze before the great cup final horse race.
Cowboy Larry O'Day and his sidekick Lucky Smith happen upon a distraught Barbara Hartwell, who is about to be arrested for the murder of her uncle. With Barbara behind bars, Larry is determined to find the real killer and soon finds himself in the middle of a mystery involving crazed German entomologists and a smuggling ring bringing Chinese "picture girls" across the Mexican border for sale to wealthy Chinese bachelors.
A industrialist has a row with his son, who leaves home. Meanwhile, both his assistant and solicitor conspire to embezzle a fortune in bonds. A plucky young newspaper reporter pursues the rich man's daughter.
A music professor is fired from his job for not knowing enough about modern "swing" music. He goes to Chicago to learn more about the subject in hopes of getting his job back, but he winds up getting mixed up with gangsters.
A federal agent and a female reporter team up to catch a criminal gang that has kidnapped a scientist in order to get his formula for a new type of poison gas.