John Wyatt (John Wayne) is a government agent sent by his boss Colonel Peters to go undercover and join a traveling medicine show to stop counterfeiters operating along the Mexican-American border. The medicine show is run by Dr. Carter (Earl Hodgins), who was just released after serving a ten-year stretch for counterfeiting. Wyatt hooks up with the show when he rescues the medicine wagon from being stopped by the sheriff and when the wagon breaks down pulls it by rope with his horse across the state-line of Arizona-New Mexico. The sheriff is after Carter for drunkenly busting up a drugstore and not paying for his order, and then running out of town. The grateful Doc Carter has John work a marksmanship act with his lovely daughter Linda (Marion Burns), which fits in with the show’s first act of the banjo strumming showmen Ike (Perry Murdock) and Mike (Gordon Clifford) crooning “When We Were Young and Foolish” and “Snap Those Old Suspenders” when Carter hawks his miracle drink in the next border town. But, unbeknownst to Carter, his former partner, Curly Joe Gale (Yakima Canutt), who framed him, is operating a counterfeit ring on the Mexican side of the border. Curly Joe has his gang kidnap Carter and his daughter, and holds them in his Paradise Canyon Mexican hideout. He fears Carter will kill him to get even for the frame job. John now knows who the real culprit is and goes after the gang with the help of the Mexican police.

This is a juvenile Western that shuns any meaningful dialogue for action scenes such as Wayne jumping off a high cliff into the water, tackling horsemen by jumping from his horse onto theirs, and a number of fistfights. Yakima Canutt was Wayne’s stuntman. The acting was below average for even this B Western series.