Tom Jeffords comes across a wounded, 14-year-old Apache boy dying from buckshot wounds in his back. Jeffords gives the boy water and treats his wounds. The boy's tribesmen appear and are initially hostile, but decide to let Jeffords go free. However, when a group of gold prospectors approaches, the Apache gag Jeffords and tie him to a tree. Helpless, he watches as they attack the prospectors and torture the survivors. The warriors then let him go, but warn him not to enter Apache territory again.
When Jeffords returns to Tucson, he encounters a prospector who escaped the ambush. He corrects a man's exaggerated account of the attack, but Ben Slade is incredulous and does not see why Jeffords did not kill the Apache boy. Instead, Jeffords learns the Apache language and customs and plans to go to Cochise's stronghold on behalf of his friend, Milt, who is in charge of the mail service in Tucson. Jeffords enters the Apache stronghold and begins a parley with Cochise, who agrees to let the couriers through. Jeffords meets a young Apache girl, Sonseeahray, and falls in love.
A few of Cochise's warriors attack an army wagon train and kill the survivors. The townsfolk nearly lynch Jeffords as a traitor before he is saved by General Oliver Otis Howard who recruits Jeffords to negotiate peace with Cochise. Howard, the "Christian General" condemns racism, saying that the Bible "says nothing about pigmentation of the skin". Jeffords makes a peace treaty with Cochise, but a group led by Geronimo, oppose the treaty and leave the stronghold. When these renegades ambush a stagecoach, Jeffords rides off to seek help from Cochise and the stagecoach is saved.
Jeffords and Sonseeahray marry in an Apache ceremony and have several days of tranquility. Later, Ben Slade's son spins a story to Jeffords and Cochise about two of his horses stolen by Cochise's people. Cochise says that his people did not take them and doubts his story, as he knows the boy's father is an Apache hater. They then decide to go along with the boy up the canyon, but are ambushed by the boy's father and a gang of men from Tucson. Jeffords is badly wounded and Sonseeahray is killed, but Cochise kills most of the men, including Ben Slade. Cochise forbids Jeffords to retaliate, saying that the ambush was not done by the military and that Geronimo broke the peace no less than Slade and his men, and that peace must be maintained. General Howard arrives with some of the townsfolk, and informs Jeffords and Cochise that the men who survived the ambush and fled have been captured and will be executed for their crime, and the townsfolk offer their condolences and apologies. Jeffords rides off with the belief that "the death of Sonseeahray had put a seal upon the peace, and from that day on wherever I went, in the cities, among the Apaches and in the mountains, I always remembered, my wife was with me".
