Mysterious Island

Capt. Cyrus Harding escapes from his Confederate captors by hijacking an observation balloon. The group crash-lands on a volcanic, uncharted (and fictitious) island, located in the South Pacific. The castaways soon encounter a group of people that include the local natives (who worship the island's volcano), Rulu (a woman from Mercury trying to extract an unnamed superexplosive element in order to conquer the Earth)