Young Nate Starbuck, the son of a famous Boston abolitionist preacher, flees the North after helping a femme fatale to steal money she claimed was hers. When Richmond landowner Washington Faulconer snatches him from the grip of a Yankee-hating mob, Nate is both grateful to and awed by his idealistic rescuer. He agrees to join the newly formed Faulconer's Legion—even though it means fighting against his native North.

But Nate's dilemma is only one of many within the Legion. Faulconer's own son cannot bring himself to fight, while his daughter's cheating fiancé plots for control of the family fortune. As they come together to march into battle, the men of Faulconer's Legion are prepared to start a war, but they aren't ready for how they—and the nation—will be forever changed by the oaths they have sworn for their beloved South.