Jerry Blake (aka Federal Operator 99) teams-up with Joyce Kingston to thwart the plans of escaped crime boss Jim Belmont.
An expedition arrives on an uncharted jungle island to rescue the local natives, led by a jungle boy, from a volcano that is about to erupt.
Escaped Prisoner 39013 impersonates the rich and influential Horace Granville, allowing him to create a variety of disasters. Fortunately, he is thwarted repeatedly by three daring circus daredevils.
Two British officers are assigned to collect information to convict Captain Kidd of piracy.
Prior to the United States' involvement in World War II, the masked vigilante Spy Smasher fights Nazi agents operating within the US, led by the treacherous sabotage leader codenamed The Mask.
Beyond Hell's Gate Pass is territory controlled by a man who calls himself King Carter; he uses a variety of schemes to prevent the railroad from being built, for fear it will finish his control of (what he considers) his land.
A young girl journeys to Africa to find her father, an explorer who vanished in the jungle.
The obsessive scientist Dr. Miller is working on a matter-transmitter invention called the Paratron; a conspiratorial team of spies and no-goods pursue him to Alaska, trying to steal the device.
Dusty Bates observes some smuggled jewels hidden in a crate aboard a ship; he is pursued by low-lifes when the crate is put ashore.
Mota is a Martian representative, who has come to impose interplanetary law on the Earth (which has become too dangerous); opposing his authority is Kent Fowler, who resists the alien plot, without understanding its details.
Calvin Drake employs a group of low-lifes to drive away land owners along the path of a new railroad; Red Ryder opposes this strategy.
Tom King Jr. seeks to discover who murdered his father, a Texas Ranger; the trail leads to a network of Axis spies.
Dr. Ernst Grood , having already dominated the planet Ergro, now intends to take over the control of the Earth. Unfortunately for him, reporters oppose his sinister designs.
A team of two-fisted insurance investigators (one of whom disguises himself as The Masked Marvel) endeavor to discover and thwart the loathsome saboteur Sakima.
Congo Bill is hired to locate an heiress lost somewhere in Africa.
A police detective is caught up in a plot to steal two million dollars in bonds.
An Indian rug is the key to the location of a lost treasure. When the rug's owner is murdered, it becomes a case for Forest Ranger Steve King
A bunch of waterfront youths pursue the Sea Raiders, a gang of saboteurs.
Beatrice Fairfax, the original advice-to-the-lovelorn reporter and her friend and not-so-secret admirer Jimmy Barton investigate calls for help and escape exotic perils and dangers. Episodes include exciting and fun stories of baby-napping, blackmail, jewel thievery, disguise, counterfeiting, and the long-unseen episode featuring entrancing cult starlet Olive Thomas and the real New York Yankees and Giants playing a game in the Polo Grounds.
Famed aviator Bruce Gentry is working with scientist Andrew Benson, setting out to uncover the origin of a deadly secret weapon---an electronically controlled flying disc which can be directed at moving or stationary targets. The disc was master-minded by an enemy agent known only as "The Recorder" because...he speaks entirely via recordings. Aided by rancher Frank Farrell and his sister Juanita "Nita" Hodges, Gentry consistently foils "The Recorders" schemes, which are carried out by "The Recorder's" henchmen, Krendon, Allen and Chandler, including an attack on the Panama Canal.