Owen Burke is at loose ends in the Mexican town of San Rafael. While at the local cantina, he overhears a conversation between two Mexican vaqueros seated nearby and decides to introduce himself. The two men work for Don Enrique Hernandez de Allende at a horse ranch some distance south. The don is planning a horse drive to the north and then west to California, where the don's brother-in-law has a ranch. Owen knows those trails and hopes the don, who has never made the trip before, might be in need of a guide.