Secret Service Major Steel (Joseph W. Girard), is one of the few men in America aware of the fact that Captain Albright (Dave O'Brien) is also Captain Midnight, daring masked aviator dedicated to fighting gangsters and enemies of America. When murderous bombing attacks are made on West Coast munitions plants, Steel sends for Albright and asks him to track down the mysterious Ivan Shark (James Craven), the foreign agent mastermind behind the attacks. Shark has learned about an ingenious range finder, invented by John Edwards (Bryant Washburn, and makes plans to obtain a model of the invention. Edwards instructs his daughter, Joyce (Dorothy Short), to bring the model to Albright for safekeeping in his mountain laboratory. Shark takes Edwards prisoner by Albright assures Joyce that her father will be saved and an end put to Shark's reign of terror. Dressing as Captain Midnight and enlisting the aid of his friends, Chuck (Sam Edwards) and Ichabod Mudd (Guy Wilkerson), Captain Midnight delivers on his promises fourteen chapters later.

An adventurer goes after Nazi spies who have a new death ray called the Paratron.

Texas Ranger tries to stop takeover of Indian lands.

The adventures of master detective Sherlock Holmes as he and his assistant, Dr. Watson--and, somewhat reluctantly, the bumbling Inspector Lestrade--battle criminals in London.

Natty Bumppo, known as Hawk-Eye, is a frontiersman in the American wilderness. Together with his Indian friends Chingachgook and Uncas, he fights battles against nefarious white soldiers as well as the vicious Indian Magua and his cohorts.

New York City policewoman Casey Jones' assignment to fight crime often entails her going undercover in some of the seediest and most dangerous parts of the city.

A crime fighter known as The Spider battles a villain called The Octopus, who is out to sabotage America and install his own government.

Enemy spies try to steal a new fighter plane.