Following the end of the Civil War, rough-hewn Mexican bandit leader Jose Esqueda warns the people in his South Texas village that they are in danger of losing their land to the homesteading "Americanos," who are descending upon the Brownsville area. While the villagers cheer Esqueda when he vows to burn down the settlers' homes, Rio, an American who was reared by Esqueda's mother and regards him as a brother, shows little support for the plan. The first hacienda the bandits set on fire is the new home built by rancher King Cameron for his wife Cordelia. Risking his life to do what he believes is right, Cameron organizes a meeting at the local church to put a stop to Esqueda's raids. Esqueda and Rio are among those attending the meeting, and when Cameron calls Esqueda a "murderer, a thief and a coward," the bandit laughs openly at his accusations. The meeting ends abruptly after Cameron vows to fight Esqueda. No sooner does Cameron rebuild his house, than Esqueda sends Rio and his men to burn it down again. Father Antonio, the respected village priest, warns Cameron that Esqueda is planning an attack on his property and, while praying for the couple's safety, helps them ward off the gang. The gun battle is cut short with the arrival of the rangers, and Rio is captured by Cameron. Instead of turning Rio over to the soldiers, Cameron offers him a partnership, and insists that the bandit help him bring over some horses from Mexico. Though Cordelia disapproves of the plan, believing that Rio should not be trusted, the two men quickly depart for Mexico. Along the way, Rio proves his trustworthiness when he saves Cameron from drowning in a river. Soon after Cameron and Rio return from Mexico, Esqueda discovers their partnership, but forgives his foster brother's apparent desertion as he believes that Rio joined Cameron because he is in love with Cordelia. Cordelia eventually comes to trust Rio, and one day, when Cameron is away, she asks him to take her to Esqueda. Angered by Esqueda's rude dismissal of her request that he end his raids, Cordelia grabs his gun and threatens to kill him. She decides not to shoot, however, when Esqueda tells her that Rio would be killed by his gang as a consequence of her action. Later, Cordelia, now in love with Rio, steals a kiss from him, but he strikes her for the impropriety. When Esqueda learns that Rio has been spurned by Cordelia, he believes that Rio will now remain loyal to him and will not interfere with a raid on the "gringo" town of Brownsville. Esqueda and his gang then shoot their way into Brownsville, kill the sheriff and rob the bank. In a drunken rage, Esqueda decides to kill Rio, Cordelia and Cameron, and sends one of his men to find them. Meanwhile, word of the siege of Brownsville reaches the Cavalry commander, who immediately sets out to regain control of the town. Esqueda's men flee when they see the approaching Cavalry, but the bandit leader stays behind to kill Cameron. After wounding Cameron with four gunshots, Esqueda is about to kill him, when Rio arrives and points his gun at him. The two face off in a gun draw and are killed simultaneously. As Father Antonio prays over the dead men, Cameron returns to the arms of Cordelia, whom he forgives for her feelings for Rio.