Cavalry captain Will Lockhart poses as a wagon train driver bringing supplies from Laramie to the small town of Coronado in order to investigate an attack by rifle-toting Indians on an Army patrol, which claimed his brother’s life. In Coronado, Will is disconcerted to find a repeating rifle at Barbara Waggoman’s mercantile store and learns that it was part of a trade with an Apache.
The following day, as Will and his men load up their wagons with salt, they are attacked by Barbara’s cousin, Dave Waggoman, who accuses Will of stealing and orders his men to rope and drag Will, then set fire to the wagons and shoot the mules. Vic Hansbro, foreman of the Waggoman Barb Ranch, arrives and orders Dave away. Will pays off his men, but old Charley O’Leary offers to stay behind, suggesting that, as his mother was an Apache, he could question the local Indians about rifles.
Will returns to Barbara’s store and she explains that her uncle Alec owns the town and she despises him for ruining her recently deceased father. Later, Will confronts Dave in town and when Vic attempts to break up the brawl, he and Will fight. Rancher Kate Canaday stops Dave from interfering, and the fight is halted only by the arrival of Alec, who demands that Will leave Coronado. Kate, who was once engaged to Alec, invites Will to her ranch, the Half Moon, and Will accepts, despite advice from town drunk Chris Boldt.
Back in town, Barbara chastises Vic, her fiancé, for appeasing Alec, but Vic insists he is invaluable to the Barb. Meanwhile, at the Half Moon, Kate offers Will a job as her foreman, but he declines, explaining that he is only in town seeking his brother’s killer. At Alec’s invitation, Will goes to the Barb, where Alec gives him restitution money, but refuses to explain why he never took action about the cavalry massacre, which occurred on his land. Later, outside of town, Will meets Charley, who discloses that the Apaches are expecting a shipment of rifles. When Will and Charley realize they have been followed, Charley heads to town and Will discovers Boldt, who offers to sell him information.
Later that evening, Will is attacked by Boldt, but after Will knocks him down, Boldt flees. Will then stops by a church celebration and learns from the priest that rifles were used by the Indians during the attack on the cavalry. On his way back to his room, Will is arrested by Sheriff Tom Quigby and accused of murdering Boldt, who was found dead shortly after his confrontation with Will.
The next day, Alec visits Will in jail and offers to arrange for a lawyer and a friendly judge, if Will agrees to leave town. When Will asks Alec why he is determined to get him out of town, Alec confesses that he is plagued by a dream in which a stranger kills Dave. Will dismisses Alec’s dream and refuses his help. Kate then bails Will out and insists he become
The Half Moon foreman. Meanwhile, at the Barb, Alec lectures Dave about his disinterest in the business side of the ranch, but Dave demands that Alec fire Vic so that he can take charge. Vic rides in with the news that Kate has hired Will and that the men suspect Will is a hired gun. Later in private, Alec confesses to Vic that he has lost most of his eyesight and pleads with Vic to protect Dave, assuring him a portion of the Barb at his death, a promise overheard by Dave.
When Dave and his men run into Will herding Kate’s cattle, Dave fires at him, but is wounded in the hand. Dave orders his men to capture Will and shoots him in the hand as revenge. Dave then heads into the mountains, where he uncovers a wagonload of rifles and sends smoke signals to the Indians, which attract Vic, with whom he has been selling arms to the Indians in hopes of creating instability in the region.
Dave insists that they should give the Indians the rifles immediately so that they will attack the Half Moon, but Vic explains that the Barb will also be attacked. After complaining about his lack of authority, Dave draws on Vic, who shoots him dead. Vic brings Dave’s body back to the Barb, while Kate and Barbara tend to Will at the Half Moon. The following day after Dave’s funeral, Alec rides out alone to the Half Moon to shoot Will, but cannot see well enough to aim.
A few days later, Alec questions Vic about the excessive cost of equipment, and when Vic blames Dave, Alec accuses him of purchasing rifles illegally. Despite Vic’s attempts to dissuade him, Alec insists on searching for the rifles. Meanwhile, Will meets Charley, who shows him deep rutted wagon tracks, which the men then follow. Vic accompanies Alec into the hills and admits buying the rifles, but insists that it was Dave’s idea. When Vic maintains that he has been more of a son to Alec than Dave, Alec is angered, and in the ensuing tussle, Vic pushes Alec down a steep ravine.*
Will later finds Alec unconscious and takes him to the Half Moon. The doctor reports that Alec is now completely blind, but will recover. Vic arrives at the Barb near dawn, believing Alec dead, and when told otherwise, grows anxious. When Alec regains consciousness he asks for Will and reveals his discovery of the rifles and that Vic is the man in his dreams. Will goes in search of Vic and finds him with the rifle wagon, signaling the Apaches. The men fight and Will forces Vic to push the wagon over a cliff before the Indians’ arrival.
Vic then escapes, but is killed by the outraged Apaches. Later, Alec and Kate make wedding plans, while Will prepares to depart after telling Barbara he hopes to see her when she returns East.