The "Rough Ridin' Kids" stir up a real hornet's nest when they become suspicious of a man named Big John Harkins, who is seen breaking in wild horses which are allegedly slated for the fertilizer-and-hide factory. At the same time, large amounts of counterfeit fifty-peso notes begin flooding Arizona near the Mexico border. That brings a Mexican police-chief Juan Reyes, posing as a bandit named Jalisco, to investigate.