The Mysterious Island presents the same characters as those from In Search of the Castaways and is also the sequel to Twenty Thousand Leagues Under the Sea. Taking place during the American Civil War, the story starts when five northern prisoners of war decide to escape to the South Pacific by hijacking a balloon. Cyrus Smith, a railroad engineer in the Union, Neb, Cyrus's servant, Bonadventure Pencroff, a sailor, Harbert Brown, Pencroff's dependent, and Gedéon Spilett, a journalist, join forc