John Eastridge, a former Confederate soldier from North Carolina, survived the decimation of his unit in the battle at Gettysburg, only to face the debilitating circumstances from months in a prison camp. When given the opportunity to win his freedom, John takes the Oath of Allegiance and joins the Union Army, enduring the slurs from his former comrades for becoming a "Galvanized Yankee." His hopes of slipping off to return to his wife and young family are dashed when he is posted to the desolation of the Dakota Territory. Now he has to win the trust of the regular Union troopers and survive against hunger, disease, the harsh weather, and attacks by Native Americans. Meanwhile, his family has their own struggles to survive the war. Prayers and letters are the threads that hold John and his family together through the trials of the Civil War.