- Directors: Howard Hawks, Arthur Rosson
- Producers: Howard Hawks
- Writers: Borden Chase, Charles Schnee
- Genres: Western, Action, Adventure
- Actors: John Wayne, Montgomery Clift, Walter Brennan
Thomas Dunson (John Wayne) is a stubborn man who wants nothing more than to start up a successful cattle ranch in Texas. Shortly after he begins his journey to Texas with his trail hand, Nadine Groot (Walter Brennan), Dunson learns that his love interest (Coleen Gray), whom he had told to stay behind with the wagon train with the understanding that he would send for her later, was killed in an Indian attack. Despite this tragedy, Dunson and Groot press on, only to chance on an orphaned boy named Matthew Garth (played as an adult by Montgomery Clift), whom Dunson effectively adopts. With only a couple head of cattle, Dunson and the boy enter Texas by crossing the Red River and Dunson proudly proclaims all the land about them as his own. Two Mexican men appear on horseback and inform Dunson that the land already belongs to their boss. Dunson dismisses this inconvenient fact, kills one of the men, and tells the other man to inform his boss that Dunson now owns the land. Dunson names his new spread the Red River D, after his chosen cattle brand for his herd. Fatefully, he promises to add M (for Matt) to the brand, once Matt has earned it.
When Matt reaches Abilene, he finds men there who have been eagerly awaiting the arrival of such a herd to buy it; Matt happily accepts an excellent offer for the cattle. Unknowingly, he has just completed the first cattle drive along what would become the Chisholm Trail. Shortly thereafter, Dunson arrives in Abilene with a posse to follow through with his vow to kill Matt. The two men begin a furious fight, which Tess interrupts by drawing a gun on both men and demanding that they realize the love that they share for each other. Dunson and Matt see the error of their ways and make peace with each other. The film ends with Dunson telling Matt that he will incorporate an M into the brand as he had promised to do years before.