During the Civil War six survivors escape from a prison camp in Richmond, Virginia by hot air balloon and find themselves on an uncharted island in the Pacific. Far from any kind of known civilization, the island is inhabited by carnivorous giant insects and animals, bloodthirsty pirates, and mad genius Captain Nemo (Patrick Stewart), who lives on the island for his own secretive ends. When Smith is rescued from drowning by Nemo's remaining crewman, he talks with Nemo about his role in the war and the atrocities committed by Nemo in his younger days, the rest of his group must try and survive without him, which becomes more difficult when one of them is eaten by a giant mantis. As Helen discovers a gold medallion with a strange map on it, Nemo tries to convince Smith to remain in his compound, but Smith refuses to abandon his friends to the island, convincing Nemo and Joseph to track and rescue the rest of the survivors from a giant ant... unaware that pirate Captain Bob Harvey is coming to the island, looking for a lost treasure said to be hidden on the island.Although Nemo refuses to allow the crew to leave, the survivors contemplate their next move while exploring the compound. Unaware of the pirates on the island, the survivors talk with Nemo about his role in the Indian rebellion, during which he reveals that his wife and daughter were killed by the British to try to find his location. Nemo reveals that he plans to prevent war by perfecting the ultimate weapon, capable of destroying an entire city, using an element unique to this island, thus making war impossible as the consequences would be too devastating if such weapons were used. He offers Smith the chance to work with him, but Smith rejects the offer, feeling that the consequences of revealing the weapon's existence would be too dangerous as there is no way to be certain how others would react to Nemo's demonstration, prompting Nemo to exile the survivors.While wandering the island, they are attacked by giant beetles, but manage to escape by jumping into a river. Following the river to the ocean, they find an old port and boat, but the boat is rotten and useless to them, and they are subsequently attacked by a giant scorpion that nearly kills Helen, Jane and Smith before Neb and Pencroff manage to kill it.Exploring the island, the survivors- after witnessing a stranger running through a wood- find a cave on a cliff which they make their new home. While out collecting food, Helen encounters Blake- one of the pirate crew left behind during an earlier raid- and shelters from a storm in the survivors' original cave with him, but he declines the offer to join them due to his past, although he advises her to conceal her medallion. Helen is later captured by a bird, but is rescued by Blake and the stranger, Blake recognizing him as Atherton, a former member of Harvey's crew who was abandoned after a mutiny.While attempting to construct a raft, they witness Harvey's ship arriving outside their cave, prompting Atherton to reveal that he was marooned rather than killed because he is Bob Harvey's brother. Helen attempts to locate and move the gold for safe keeping, but is captured by Harvey's men, prompting Blake to suggest a raid on the ship to rescue her. The rescue succeeds- the pirates' superior numbers being defeated by the element of surprise and Blake and Atherton's experience with the ship, allowing Pencroff to steal the amulet comprising the other half of the medallion's map-, but Blake is shot as they are escaping.Having returned to shore, the crew meet Joseph, who provides them with repeating rifles to use against a new wave of pirates. During the subsequent fight, the survivors manage to drive off the pirates when Atherton forces Harvey into a stand-off, but Joseph is shot while departing. Staggering back to Nemo's home, Joseph pleads with Nemo to realize that he needs the survivors to remind him of what it means to be human, noting that they are still innocents despite Nemo's disappointment with the rest of the human race.Angered at the survivors' defiance of him, Harvey begins to fire the ship's cannons at the cave house, destroying the raft the survivors were attempting to build, but the ship is destroyed by Nemo. As the others begin work on a new raft, Pencroff departs to try to find the treasure- needing the money to pay off his debts back in America-, but the cave where the treasure is kept is also home to gigantic spiders that kill him despite Neb's attempt to save him.As they attend Pencroff's funeral, Nemo appears to them, revealing that his equipment has detected seismic activity that suggests that the island's volcano is about to erupt. Although he provides them with the location of a boat at his compound, he attempts to recover his equipment and plans from the Nautilus, resulting in him being trapped in the Nautilus as a lava flow fills the cavern where the ship was kept, leaving the remaining survivors to retreat in the offered boat and hope that they will find a way home.
Output: Question: What attacks the group when they arrive?, Answer: wild boars