Synopsis: Cattle ranchers Belknap and Selby plot to send their cattle to market before agricultural inspector Gene Autry can confirm the presence of hoof-and-mouth disease. Learning a veterinarian is also on the way to inspect, Belknap and Selby move their infected cattle to the ranch of unsuspecting Jim Wheeler and his daughter. Suspicious, Gene and his partner, Frog, investigate and unearth a complex plot.