Lassiter, a Texas Ranger, vows to avenge himself against the man who caused his married sister to abandon her husband and join the Mormon sect. At Jane Withersteen's ranch, where his sister was last seen, Lassiter befriends a rider named Venters, falls in love with the ranch's beautiful owner, and takes a little orphan named Fay Larkin under his wing. While Venters searches for a band of rustlers that has been raiding Jane's ranch, Lassiter learns that his sister is dead and then raids a Mormon meeting, killing Dyer, the man who abducted her. Venters captures the leader of the cattle thieves, who proves to be a young woman, and soon the two fall in love. Pursued by the angry Mormons, Lassiter, Jane and Fay ride to a secluded valley where they meet Venters and the repentant cattle thief, whom Lassiter recognizes as his dead sister's daughter. Venters and the girl escape the Mormons, but Lassiter, in rolling a huge boulder down on his pursuers, blocks the only exit to the valley, trapping himself, Jane and Fay inside.