It's May 1863. Out-generaled and out-gunned, a demoralized Union Army has pulled back with massive losses at the Battle of Chancellorsville. Fort Sumter, hated symbol of the Rebellion, taunts the American navy with its artillery and underwater mines. In Beaufort, South Carolina, one very special woman, code named Moses, is hatching a spectacular plan. Hunted by Confederates, revered by slaves, Harriet Tubman plots an expedition behind enemy lines...