Lieutenant Zachary Tarrant is cashiered out of the U.S. Army for his involvement with Tamar Young, the daughter of Mormon leader Brigham Young. Tarrant was unaware that Tamar is actually the third wife of Hyrum Paine, secretary to Brigham Young. His one hope for reinstatement is to accept an assignment as a government spy, to go to the Mormon city of Moroni and gather evidence on Bishop Lot Drake who, thirty years before, was responsible for the massacre of 120 Gentile immigrants at Mountain Meadows.