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

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.

Deadwood Dick, a masked and mysterious hero, is in reality Dick Stanley, editor of the Dakota Pioneer Press and a leading member of Statehood For Dakota. He is on the trail of a masked villain known as the Skull, who leads a violent, renegade band infamous for its violence against the Deadwood residents' wishes for a statehood status.

Professor Davidson and his niece Diana Palmer search Africa for the Lost City of Zoloz, reputed to be the source of a large hidden treasure. Also searching is a local crook, Singapore Smith, and Dr. Max Bremmer, who plans to destroy the peace in which the native tribes have been living. However, Godfrey Prescott, otherwise known as the Phantom, is feared and respected by the natives and is able to circumvent the traps and schemes of the villains.

Dr. Herbert Lee (John Paul Jones), an archaeologist seeking to decipher ancient Mara inscriptions, is aided by his son, Terry (William Tracy), and Terry's pal, Pat Ryan (Jeff York), and Normandie Drake (Joyce Bryant). Fang (Dick Curtis), a jungle pirate and warlord,plots to kill The Dragon Lady (Sheila Darcy), Queen of the Temple of Mara, and seize the treasures of her ancestors. Both Fang and The Dragon Lady have sworn death for any foreign intruders.

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.

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

The Eagle uses sky writing to make threats against a corporation. Nathan Gregory owns a traveling fairground and is thought to be the Eagle. Craig McCoy is a pilot who goes looking for the Eagle when Gregory turns up missing.

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.