A possibly mad cavalry commander leads his troops through dangerous Indian territory.

After an Indian attack decimates much of 'C' Troop and kills their captain, command of the troop falls to the only non-commissioned officer left alive, Sergeant Vinson. The few survivors include Travis, a college-educated drifter, and McGurney, an anti-authoritarian Irishman. Vinson, who has a great hatred for the Apaches, decides to head for Fort Crane, some hundred miles away, and hopes to meet up with the cavalry's main column en route. Travis and the troop's Indian scout, Pawnee, report that the Apache have occupied a waterhole up ahead and that there is no sign of the main column. As there is no other route, Vinson decides to attack the Apache even though they are outnumbered four to one. After a long, brutal battle, the soldiers succeed in driving the Apache away. When Vinson kills an Apache as he appears to be about to surrender, the soldiers begin to think of him as a butcher. Later, they encounter Tucker and Moss, the only survivors of the massacred main column. Vinson elects to push on to the fort despite the main column's demise, but decide to take a longer route. Travis learns from Vinson that, five years before, Vinson's wife and two children were ambushed by Apaches and that before dying, his wife shot their children rather than have them taken alive. In an area normally out-of-bounds to the troops, they come upon an old couple, Charlie and Adele, who are trading with a young Apache brave, Moving Cloud. Vinson takes the brave hostage, hoping to guarantee their safe passage to the fort. He places Pawnee in charge of Moving Cloud, but they become involved in a knife fight in which the young Apache kills Pawnee, then escapes. Farther on, the troop approaches a cliff dwelling, which is inhabited by an old Paiute Indian and his seventeen-year-old granddaughter. Vinson tells Travis that he expects that the men will file charges against him when they reach the fort, but Travis says that he is proud to serve with him. After the grandfather warns Vinson that he can hear many horsemen headed their way, Vinson, fearing it may be an Apache scouting party, elects to stay where they are rather than be caught out in the open. Although the Paiutes also fear the Apaches, Vinson will not permit them to leave, in case they alert the Apaches to the troop's whereabouts. When a small band of Apaches come to the cliff dwelling, they are welcomed by the old Paiute while the soldiers hide. Although the Apaches take the granddaughter prisoner, the grandfather does not reveal the soldiers' presence. Overcome by his hatred of Indians, Vinson opens fire on the Apaches, who then massacre all except Vinson, Travis and another trooper, Collins. When Vinson orders the old Paiute to ride to Fort Crane for help, he accuses Vinson of shooting the Apaches when they were about to leave and says he will tell the truth about what happened. As Vinson moves to shoot the old man, Travis shoots and kills Vinson, then tells Collins that Vinson was as fine a man as he ever knew, and that although he fought to control the hate which festered within him, it finally overcame him.