The Last Frontier

Captain Bob Dayton and Lieutenant Ed Carey are partners in a company called "Sky Raiders" which seeks US government contracts for its inventions. Enemy spies attempt to steal, sabotage and discredit the inventions and founders of the company.

Four youthful cadets are implicated in a series of murders, and must attempt to clear themselves of suspicion.

An escaped criminal impersonates a Police Commissioner, causing no end of trouble to a determined Federal Agent.

Man-woman team of investigators uncover a gang whose mad scientist leader has developed an invisibility chemical and plans to build a mercenary army of invisible men.

An accomplished aviator sets out to locate treasure hidden by one of his ancestors. He encounters interference from various adversaries.

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.

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.

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.

A young girl journeys to Africa to find her father, an explorer who vanished in the jungle.