Soldiers escaping the American Civil War take flight in a giant observation balloon and land far away on a strange uncharted island, where they encounter giant creatures, cut-throat pirates, two shipwrecked Englishwomen - and the mysterious Captain Nemo. Sci-fi adventure based on Jules Verne's novel, starring Michael Craig, Herbert Lom, Joan Greenwood and Michael Callan, with special effects by Ray Harryhausen.

During the US Civil War, Union POWs escape in a balloon and end up stranded on a South Pacific island, inhabited by giant plants and animals. They must use their ingenuity to survive the dangers, and to devise a way to return home. Sequel to '20,000 Leagues Under the Sea' .