The film opens in the Wyoming Territory in 1876. Duncan McKaskel, his wife Susanna, and their 12-year-old son Tom are travelling West, hoping to start a new life. They have left a cholera-stricken wagon train and arrive in a small, dilapidated town, where they meet no-good Doc Shabbitt and ask for directions. He suggests they stay in a deserted local building, but McKaskel senses danger and they leave. Shabbit decides to steal two of their horses. Con Vallian is chasing a mixed-race Indian, the latest recruit to Shabbit's gang whom, it transpires, he has tracked for hundreds of miles for personal reasons. Vallian witnesses the homesteader's encounter with Shabbit and turns up at the McKaskel's wagon during supper. He tells them their horses have been stolen. Against Susanna's advice, Duncan rides into town and tries to reclaim the horses. An intense gunfight ensues when Vallian, who has secretly followed him, shoots some of the Shabbit gang. When Doc Shabbitt finds that his son, who was about to shoot McKaskel in the back, has been killed, he vows to pursue the family and seek revenge. Susanna, Duncan, and Tom flee in their covered wagon, trying to keep ahead of their pursuers. Vallian keeps arriving to help protect them from Shabbitt and his gang. As time passes, Vallian manages to kill the bandits one by one, but the remaining four keep up their pursuit. Vallian is obviously attracted to Susanna, and she to him. Following a moment of high drama, she succumbs to his advances and they share a passionate kiss. McKaskel never learns of the kiss, but several times he tells Vallian, who is critical of his apparent pacifism, to back off. In an encounter with Indians, Susanna learns that her brother, an army officer, has likely been killed at the Battle of the Little Bighorn. Out hunting, Vallian is ambushed and shot by the Indian. McKaskel removes the bullet, but Vallian runs a high fever and falls on the trail. He is rescued and nursed back to health by Susanna. Eventually, they arrive at the small cabin Susanna's brother had built for them, on the spread where they intended to raise cattle. The family begins settling in the house, but Shabbitt and his gang show up for their revenge. A showdown ensues in which Vallian and the McKaskels manage to kill them. Vallian then bids farewell to the family and leaves to resume his solitary life.
