Flash Gordon, Dale Arden and Dr. Zarkov return to the planet Mongo for an antidote to the Purple Death, which wreaking destruction on Earth. However, Ming the Merciless has other plans for them.

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."

The struggle over the Bellamy estate ends with Michael Bellamy accused of murder and killed on the way to prison, while his brother, Abel Bellamy, takes control of the estate for his own nefarious plans.

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.

The masked hero leads a fighting force to fight a villian who plots the conquest of The Republic of Mexico.

A master criminal called The Spider puts the famous detective's brother under a hypnotic spell and turns him against Dick.

Enemy spies try to steal a new fighter plane.

American adventurer Richard Grant is falsely accused of murdering an Indian noble and escapes to Africa in search of diamond field and the real culprit.

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.