rescue of Top from a dugong, the appearance of a box of equipment (guns and ammunition, tools, etc.), and other seemingly inexplicable occurrences. The group finds a message in a bottle directing them to rescue a castaway on nearby Tabor Island, who is none other than Tom Ayrton (from In Search of the Castaways). On the return voyage to Lincoln Island, they lose their way in a tempest but are guided back to their course by a mysterious fire beacon. Ayrton's former companions arrive by chance on Lincoln Island and try to make it into their lair. After some fighting with the protagonists, the pirate ship is mysteriously destroyed by an explosion. Six of the pirates survive and kidnap Ayrton. When the colonists go to look for him, the pirates shoot Harbert, seriously injuring him. Harbert survives, narrowly cheating death. The colonists at first assume Ayrton has been killed, but later they find evidence that he was not instantly killed, leaving his fate uncertain. When the colonists rashly attempt to return to Granite House before Harbert fully recovers, Harbert contracts malaria but is saved by a box of quinine sulfate, which mysteriously appears on the table in Granite House. After Harbert recovers, they attempt to rescue Ayrton and destroy the pirates. They discover Ayrton at the sheepfold, and the pirates dead, without any visible wounds except for a little red spot on each of them. The island is revealed to be Captain Nemo's hideout, and home port of the Nautilus. Having escaped the Maelstrom at the end of Twenty Thousand Leagues Under the Sea, the Nautilus sailed the oceans of the world until all its crew except Nemo had died. Now an old man, Nemo returned the Nautilus to its secret port within Lincoln Island. Nemo had been the mysterious benefactor of the settlers, providing them with the box of equipment, sending the message revealing Ayrton, planting the torpedo that destroyed the pirate ship, and killing the pirates with an "electric gun". On his death bed, Captain Nemo reveals his true identity as the lost Indian Prince Dakkar, son of a raja of the then-independent territory of Bundelkund and a nephew of the Indian hero Tippu-Sahib. After taking part in the failed Indian Rebellion of 1857, Prince Dakkar escaped to a desert island with twenty of his compatriots and commenced the building of the Nautilus and adopted the new name