The owner of a town’s stagecoach line and a leading citizen, is opposed to
the Idaho Territory becoming a state. He kills the owner of the town’s
newspaper for endorsing it. The newspaper owners sister, an expert with a
bullwhip and pistol, dons a mask and black costume to become "The Black Whip",
dealing a blow to the gang each time they perform some heinous act in their
efforts to keep the town, and their power over it, unchanged.
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?
The war lords of a potential enemy of the US has the spy ring, led by John Baroda, the Spy King and his aide Nitra, sabotaging the plans for a vast defense system of radar stations along the American borders. Radar Defense Bureau operative Chris Calvert comes to the rescue of a brilliant radar scientist, Joan Hughes, who has been kidnapped by Baroda henchmen in chapter 1 ("The Fatal Fog"), and the two battle together before putting an end to the Spy King in the aptly-named chapter 12, "Day of Reckoning".