Set in 1863, the Civil War has ravaged the South and Charleston lays in ruins. A secret weapon, the first submersible vessel, is the last hope for the Confederates stranded within the Union's blockade. Previous attempts to use the submarine have failed, resulting in the death of twenty men, including the inventor Horace L. Hunley. The invention seems like a failure until young Lieutenant George Dixon attempts to commandeer the Hunley and strike a blow against the Union blockade. Based on a true story.