At the swanky Desert Springs Hotel in Arizona, four miles from the Mexican border, Patricia Huntley, the spoiled, wild-living granddaughter of wealthy Jeremiah Huntley, provokes the ire of border patrolman Bob Wallace by defiantly smoking in a restricted area of the forest reserve when Bob interrupts her outing with Courtney Maybrook, a jewel smuggler. After Pat rips up the citation Bob has written, he takes her to headquarters, where his captain, believing Pat's lies that Bob used obscene language and manhandled her, orders him to apologize. Bob does, but also hands in his badge. Conscience-striken, Pat insists that her grandfather find Bob a job. Upon meeting Bob, Huntley is greatly impressed with Bob's observation that Pat is headstrong and willful like a horse, and that a horse can be broken if a bridle is slapped on to make it easy to guide. He hires Bob as Pat's "guide," and she warms up to him as he takes her swimming and riding. However, when she realizes his arrangement with her grandfather, she throws a temper tantrum and threatens to get drunk and embarrass her grandfather. When the hotel employees refuse her more than one drink, money advances or a car to drive because of "Mr. Wallace's orders," Pat is furious. Meanwhile, Riker, a federal agent, tells Bob that he suspects that the thieves who stole the valuable Borloff necklace may try to take it across the border near the hotel. After Maybrook's cohorts, who have the necklace in Mexico, complain of heightened border security, Maybrook plans to secretly hide it with Pat, whom he knows will not be searched. After Pat, frustrated with Bob's "persecution" of her, slaps him, he threatens her with a whip, but the slap convinces him that the strategy is a mistake. He plans to leave, but learns that Riker is suspicious of Pat. When Huntley tells Bob that Pat left a note saying that she is going to marry Maybrook in Mexico, he borrows Huntley's car and speeds across the border. After the necklace is hidden in Pat's purse by Maybrook's cohort, Pat and Maybrook are about to be married when she backs down. Maybrook struggles with her, but Bob arrives, socks him and leaves with Pat. The smugglers chase them through the desert and shoot their tire, forcing them to stop. After Pat throws the purse down while running, she and Bob are captured, but while she leads Maybrook to the purse to save Bob, he overpowers his two guards. Maybrook finds the purse and attempts to deceive his pals by driving away with Pat, but Bob jumps into his convertible from a hilltop and overpowers Maybrook. As Bob drives the smugglers back, Pat facetiously apologizes to Maybrook for keeping his gun pointed at him by saying "Sorry, it's Mr. Wallace's orders," and then kisses Bob's bruised eye.