In the 1860s, governors from three territories east of the Rocky Mountains are joined by federal agents in their quest to find outlaw Zeb Bascomb and stop his gang of bandits. John Fulton, the head of the federal agents, and the governors know little about the elusive Zeb, except that he has a rope burn scar on the back of his neck. One day, when Elder Moab McCabe, a lone Mormon missionary, rides into Zeb's territory on horseback, Zeb's partner, Bart Yancey, a white renegade reared by Indians, kills him in cold blood. Zeb and Bart later learn that a federal manhunt is underway, and decide to split from the gang and take refuge with Elijah Walker's Mormon caravan. Posing as new converts, Zeb and Bart join the Mormons on their journey to Utah. Zeb and Emmy, the young granddaughter of missionary Abbey Hanks, become fast friends, and Zeb soon discovers the drawbacks of being a new convert when he and Bart are assigned to do heavy work for the unmarried women in the caravan. While Zeb chooses to work for Abbey and the widow Annie Fremont, Bart goes to work for sisters Tillie and Lucy Lovejoy. One day, the caravan picks up Jimmy Holden, one of Zeb's gang, who has been shot and left for dead. Jimmy is nursed back to health by Dr. Luther Mason and his nurse Dora, who falls in love with the young outlaw. When Zeb discovers that the wagon train is carrying a cache of gold that the Mormons intend to use to build a hospital, he and Bart devise a plan to steal it. Ignoring Jimmy's warning to stay out of trouble, Zeb and Bart begin searching all the wagons for the hidden gold. While the wagon train attempts a dangerous river crossing, Emmy falls into the water and is rescued by Zeb, who has developed a fatherly love for the girl. Late that night, Emmy, believing that Zeb no longer loves her, runs away from the caravan camp. Zeb finds Emmy, but soon after he returns her to the wagon train, she becomes ill. Realizing that his love for Emmy is stronger than his determination to steal the gold, Zeb decides to forgo the theft and stay with Emmy. Bart, however, tries to steal the gold on his own, and shoots Elijah while fleeing the camp. In his dying words, Elijah appoints Zeb as the new leader of the Mormon group. Zeb's first challenge as the caravan leader is to protect it from an impending Indian attack that Bart has incited, and he succeeds in doing so by risking his life and riding his horse through Indian territory to get help from a nearby fort. Zeb returns to the camp with U.S. Cavalry reinforcements just in time to save the Mormons from an Indian massacre. Zeb kills Bart, but during their struggle, Fulton discovers Zeb's rope burn and arrests him. After bidding Emmy and the others farewell, Zeb leaves the caravan to serve his time in prison.