A 14-episode serial in which Mala, a Polynesian in the employ of U.S. Intelligence investigates sabotage on Clipper Island. A gang of spies causes the eruption of a volcano, for which our hero is blamed. He convinces the local Princess Melani of his innocence and helps her ward off a takeover by rival high priest Porotu.

Tarzan, who has returned to Africa after living in England, sets off to Guatemala in search of an old friend who may have survived a plane crash there. Also in Guatemala are Ula Vale and Major Martling who are out to find the riches of the Green Goddess. They join forces after they learn that a competitor, Raglan, has already set out ahead of them. Tarzan has to rescue everyone after they are taken prisoner. When they get to the hidden city, Tarzan finds his friend alive and the fabulous treasure.

Corporal Larry Grant and Sergeant "Mac" McGowan, of the United States Marine Corps, are rival for the love of Frances Schiller, but team up to hunt down "The Tiger Shark," a mad, scientific wizard who is holding Sergeant William Schiller, Frances' brother, a prisoner on a wild, jungle island in the Pacific.

Enemy spies try to steal a new fighter plane.

Tom Wayne rescues Clancy, Renard and Schmidt in the Arabian desert and they join him in going after El Shaitan, a bad guy who is never seen as he tries to wipe out the Foreign Legion.

When his father is killed in a train wreck, Larry Baker vows to unmask a mysterious criminal called "The Wrecker," who has targeted the L&M Railroad for deadly" accidents."

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 murderous gang of counterfeiters has kidnapped the government's best engraver and is forcing him to print virtually undetectable phony money. The Secret Service sends its toughest agent, Jack Holt, and a female partner after the gang.

Hank Davis, foreman on a huge dam project, enlists the aid of his two flyer friends when a sinister figure known as The Black Ace leads his Mystery Squadron of masked pilots in an attempt to destroy the dam.