It is 1849, and Sarah Ann Thirkell is home from boarding school when she spies her father talking with two strangers near the bogs of Yorkshire, England. After her father invites the strangers to dinner, they tell of a prophet who will come to save the world, just as Jesus once did. As Sarah quietly listens, she has no idea that the two missionaries have just changed not only her life, but also the lives of everyone in her family. It is not long before the Thirkells are recruited to become Mormons bound for a new life in America. Assigned to sail with a Mormon leader, the Thirkells carefully listen as he promises a life of harmony and brotherhood if they serve their leader well. Sarah's mother, Mary, is already wary of the voyage, but when she hears a rumor that the men are expected to take plural wives once they arrive in America, she panics and forces her husband to promise he will never bring another woman into their home. And with that, their heartbreaking, frustrating journey to America begins. Based on a true story, But One Husband shares a fascinating glimpse into the Mormon way of life as a family makes their way to Utah by wagon train and suddenly fi nds themselves in the middle of the opposite of two missionaries' promises.