The California-Yucatan Railroad, being built for the good of Mexico, is under siege by a gang of terrorists hoping to force its sale; no one can prove their connection to profiteer Marsden. Manuel Vega, aged co-owner, calls in the aid of his nephew James, great-grandson of the original Zorro. Alas, James seems more adept at golf than derring-do; but after he arrives, Zorro rides again! Can one black-clad man on horseback defeat a gang supplied with airplanes and machine guns?

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

A group of flying cadets have to clear themselves of a murder charge, while trying to stop a traitorous scientist from selling secrets to the Nazis.

Texas Ranger tries to stop takeover of Indian lands.

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.

A group of street kids battle a terrorist gang led by a Japanese spy.

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.