At the impoverished hacienda of Don José, near the Mexican border, five men, headed by Farrell, stop with truckloads of vegetables, but the rancher's dog, Rinty, detects the presence of the Chinese the men are smuggling. Farrell, who covets Pepita, the rancher's daughter, plans to buy the ranch for smuggling operations; meanwhile, Dave and Dusty, two apparent tramps who are border agents, discover the smugglers' ruse, and Pepita and Rinty take an interest in Dave. Don José innocently falls in with the plans of Farrell's men. Following a series of complications, Dave is captured by the smugglers but is saved in a last-minute rescue by Rinty. The border patrol subdues the gang at the ranch, and Rinty overpowers Farrell as he flees in an automobile.