During the Civil War, Union forces blockade the port of Charleston so the Confederate army seeks a way to attack the Yankee ships. George Dixon is part of the group of men given the task of creating and building the "fish boat," a submarine. The H.L. Hunley does ultimately set out on its mission to sink Yankee ships, but fails to return, its whereabouts unknown. For over 100 years, the mystery of the Hunley and the fate of its crew stayed buried. The story of the H.L. Hunley recounts the story of the "fish boat," through its creation and mission, to its ultimate recovery and final voyage home.