War-weary Federal officers attempt a deadly mission during the waning days of the Civil War--to dishornor the South and secure the cooperation of the defeated Rebels for the Reconstruction. Then, a disastrous explosion by a small group of Federals is blamed on a young lieutenant. Court-martialed in disgrace, he is left alone with his secret and his "soldier's heart". His fate is left to his sister and best friend, a Pinkerton detective, who offers him one last chance at redemption.