In 1876, together with his fiancée, Martha Kellogg, Captain Tom Benson returns to his command under General George Custer. As they approach the fort, Tom notices that the garrison flag is not flying. Leaving Martha behind, Tom investigates and discovers that the fort is largely deserted. From Charlotte Reynolds, a distraught soldier's wife, Tom learns that most of the soldiers were massacred during a battle with the Sioux at Little Big Horn. Charlotte accuses Tom of deliberately avoiding the battle when he left the fort to fetch Martha. Although Tom insists that Custer gave him permission to leave, and that he did not know the battle was to take place so soon, the surviving soldiers are not convinced. Tom, who was Custer's right-hand man, is shocked to hear the other soldiers blame Custer's incompetence and ego for the defeat. Despite the bad feeling toward Tom, Martha remains supportive, but he decides to send her away so that she will not be affected by his blackened reputation. His plans are interrupted by the arrival of Martha's father, Colonel Kellogg, who has been charged with investigating the massacre. During the inquiry, Major Reno reveals that Custer made several serious mistakes, among them dividing his force into three battalions, which contributed to his defeat. Another soldier states that Custer began the attack against the advice of his scouts. When Tom tries to defend Custer, Kellogg orders him confined to quarters. Later, when asked why he left the fort on personal business so close to the time of the coming assault, Tom replies that Custer gave him direct orders, but because the orders were verbal, he has no proof. Determined to clear himself of charges of cowardice, Tom volunteers to lead a burial detail that has been ordered by President Ulysses S. Grant to remove the bodies of the officers from Little Big Horn. Tom "persuades" the soldiers who did not fight in the battle because they were in the stockade to volunteer along with him. As the detail travels toward Little Big Horn, Tom must contend with hostile soldiers as well as the threat of Indian attack. Near Little Big Horn, the soldiers encounter a warning indicating that Sitting Bull has made the site a sacred place for the Sioux, and the men become certain that they are riding into an ambush. Meanwhile, at the fort, Corporal Morrison returns and informs Martha that he heard Custer order Tom to leave. Then mounted on Dandy, a double for Vic, the horse that died with Custer, Morrison hurries to deliver the news to Tom. At Little Big Horn, the soldiers remove the officers' bodies and load them in wagons to be carried back to the fort. While they are working, the Sioux surround them. Young Hawk, a Sioux who was educated by whites, tells Tom that the soldiers are defiling sacred ground. He explains that the Sioux believe that the spirits of the dead men and horses live on in the Indians who defeated them in battle. When Tom dismisses his concerns as superstition, Young Hawk adds that if Custer's body is removed, his spirit would go with him and the fruits of their victory would be lost to the Sioux. When Tom still refuses to leave without Custer's body, the men rebel. Rather than further defile the sacred ground by shedding more blood, the Sioux surround the soldiers, planning to wait until they die. Meanwhile, Morrison approaches Little Big Horn. After he is killed by a lookout, the riderless horse continues to Little Big Horn. The Sioux recognize the horse as Custer's and, believing him to be the spirit of the dead Vic, disperse. Tom takes advantage of Dandy's appearance to bring his men home. Kellogg apologizes and gives his blessing to Martha and Tom's marriage.