The film stars Armand Assante, Donald Sutherland, Alex Jennings, Michael Dolan, and Christopher Bauer, and is based on the true story of the H. L. Hunley submarine and the action of 17 February 1864.

Dixon flashes back to the Battle of Shiloh, where a gold coin given to him by his wife (who was later killed in a steamboat explosion caused by a drifting mine) deflected a bullet and saved his life.

The USS Housatonic is ordered to change its position in the harbor and always be ready to steam, meaning it cannot hang metal netting over the side.

The Hunley's second in command, Lt. Alexander, is ordered to Mobile, Alabama, and a young soldier who had been volunteering to join the crew is allowed to do so.

General Beauregard attends a memorial service in Charleston for the Hunley and her crew, while inside the flooded submarine, Dixon sees a vision of his wife, welcoming him into the afterlife.