A proper English gentleman, traveling in the American West, inadvertently stops an Indian attack on the stagecoach in which he is a passenger. When the stage gets to the nearest town, the raucous Fractured Jaw--which is being plagued by unruly cowbys, bandits and marauding Indians--the story spreads, and he is appointed sheriff.

At his manor house in the English countryside, the wealthy Lucius Tibbs consults his solicitor, Mr. Toynbee, as to the whereabouts of his ne'er-do-well nephew Jonathan. Jonathan is soon located in the coach house working on his latest invention, a horseless carriage. When Jonathan's invention fails miserably, he decides to enter the family firm, the venerable Tibbs and Company, purveyors of guns and hunting rifles since 1605. Jonathan quickly realizes that the company, stuck in archaic ways of doing business, is turning only a small profit, so he sets off for America to sell Tibbs firearms in the "Wild West." While traveling by stagecoach, the bemused Tibbs finds himself in the company of a drunk and a hair tonic salesman. The stagecoach is attacked by Indians, but Tibbs, blissfully unaware of the danger and excited about the prospect of meeting a real Indian, jumps off the stage and walks up to a brave about to launch a tomahawk. Tibbs rescues the stage by restraining the Indian with his walking stick, then forces the confused warrior to shake his hand as a gentlemanly gesture of peace. The stagecoach enters the town of Fractured Jaw where the locals praise Tibbs for his bravery. Soon, however, the town's bad element, mercenaries involved in a feud over water rights between the Box N and Lazy S ranches, challenge Tibbs to a gunfight, but quickly disperse when he draws his gun with lightning speed. Tibbs checks into the local hotel and meets its proprietess, a buxom blonde named Miss Kate, who warns him that Fractured Jaw is a lawless town which has been without a sheriff for six months. Late that night, Tibbs is awakened by noise emanating from the hotel's rowdy barroom, where Kate sings and dances. When he goes downstairs to complain, Kate and the patrons make fun of his sense of decorum, and Tibbs is lured into a drinking contest by the malevolent Keeno, a Box N mercenary who mistakenly believes that Tibbs is working undercover for the Lazy S. A brawl ensues in which Keeno is shot dead, but the barroom quickly returns to normal after Kate casually orders the body removed and drinks for everyone. Seeing Tibbs's shock at the bar patrons' cavalier response, the mayor, Doc Masters, explains that the townspeople's cynicism is the result of their inability to retain a sheriff. Before he knows it, an inebriated Tibbs has been tricked into accepting the position. The next morning, Tibbs attempts to relinquish the badge, but the mayor refuses to accept it, especially after Tibbs skillfully disarms Bud Wilkins, one of the Lazy S henchmen, with his quick draw. Impressed, Kate flirts with Tibbs, but soon learns that Tibbs's lightning draw is the result of a special spring device he keeps up his sleeve. Kate, who finds Tibbs's Old World manners charming, advises him to keep his inability to shoot a secret and offers to give him lessons. During target practice, Kate and Tibbs declare their attraction to each other and Tibbs proposes marriage. Kate accepts on the condition that Tibbs give up his sheriff's badge, but Tibbs refuses because he now feels an obligation to clean up Fractured Jaw. The town undertaker begins shadowing Tibbs, certain that he will soon be adding him to the collection of sheriffs in Boot Hill Cemetery. Later, while attempting to sell guns to a local farmer, Tibbs succeeds in stopping a gun battle between representatives of the feuding ranchers, both of whom swear revenge on the new sheriff. Riding back to town, Tibbs is kidnapped by Indians and strung up for target practice, but Running Deer, the Indian whom Tibbs met on the way into Fractured Jaw, praises Tibbs's bravery and the tribe ends up making him an honorary member. Given the choice between becoming a "dead Englishman or a live Indian," Tibbs drinks the blood of a wild buffalo and smokes the peace pipe, but stops short of accepting the chief's offer of an Indian bride. Meanwhile, in town, the war between the ranchers escalates, but both sides decide to stop fighting temporarily while they concentrate on getting rid of the annoying Sheriff Tibbs. After Tibbs attempts to reason with the men and they respond by taking a potshot, Tibbs calls on the Indians for assistance. The Indians succeed in routing the ranchers, who are then taken to jail, after which the undertaker finally leaves, realizing that Tibbs is there to stay. Tibbs appoints Running Deer to the position of deputy and then begins the task of civilizing his Indian blood brother, first by teaching him how to make a proper cup of English tea. Having finally won the respect of the feuding ranchers, Tibbs elicits a promise that they will peacefully share the local watering hole with one another and with the Indians. As bells chime, an exuberant Sheriff Tibbs changes into formal wear and heads over to the chapel to wed Miss Kate, who is given away by Tibbs's adoptive father, Chief Red Wolf.