The third novel in the 'Mysterious Island' trilogy follows the adventures of some British ballooners who have crashed on a remote Pacific island and struggle to survive among pirates and escaped convicts. As a group they are very resourceful, but they do occasionally get a helping hand from a mysterious, unknown benefactor. This book closes the legend of Captain Nemo, the hero from Twenty Thousand Leagus Under the Sea.

Excerpt:
"It was now two years and a half since the castaways from the balloon had been thrown on Lincoln Island, and during that period there had been no communication between them and their fellow-creatures. Once the reporter had attempted to communicate with the inhabited world by confiding to a bird a letter which contained the secret of their situation, but that was a chance on which it was impossible to reckon seriously. Ayrton, alone, under the circumstances which have been related, had come to join the little colony. Now, suddenly, on this day, the 17th of October, other men had unexpectedly appeared in sight of the island, on that deserted sea!"