20,000 Leagues Under the Seas recap

French naturalist Pierre Aronnax joins the frigate Abraham Lincoln with his servant Conseil and Canadian harpooner Ned Land to hunt a supposed sea monster. The quarry proves to be the Nautilus, a technologically advanced submarine commanded by Captain Nemo. After the three men fall overboard, Nemo takes them in but refuses ever to release them. Aronnax is captivated by undersea forests, lost wrecks, strange animals, a coral cemetery, the ruins associated with Atlantis, and a journey beneath Antarctic ice; Ned continually seeks escape. Nemo rescues a pearl diver, aids people resisting oppression, and reveals both compassion and a consuming hatred of the nations of the surface. After giant squid attack the Nautilus and a crewman dies, Nemo grows increasingly remote. He later uses the submarine to sink a warship. Near Norway, the captives attempt to flee as the Nautilus enters the Maelstrom. Aronnax, Conseil, and Ned survive and reach land, but Nemo and his vessel disappear, their fate unknown.

Ships around the world report collisions with a fast, luminous object large enough to damage their hulls. Public debate alternately treats it as a sea animal and an unknown vessel. Professor Pierre Aronnax, a French authority on marine life, supports the theory of an enormous narwhal and accepts a place on the American frigate Abraham Lincoln, sent to find the danger. His loyal servant Conseil joins him, and aboard ship they meet Ned Land, a Canadian harpooner who doubts that any animal could cause the reported damage. After a long search, the frigate sights the object and attacks. The quarry outruns the ship and then strikes it. Aronnax is thrown into the sea; Conseil follows to help him, and they find Ned alive on the hard surface of the supposed animal. The surface is metal. A hatch opens, and unknown men pull all three inside.

Aronnax, Conseil, and Ned are confined inside the mysterious vessel. Ned responds angrily to captivity, while Aronnax studies their surroundings and tries to communicate with the crew. Their commander finally introduces himself as Captain Nemo. He explains that the supposed monster is the Nautilus, a submarine he designed and built in secrecy. It is powered by electricity and supplied largely from the sea, allowing Nemo and his crew to live beyond the authority of any country. Because the three prisoners now know his secret, he will not return them to land, but he grants them freedom to move around the vessel and invites Aronnax to share in its scientific discoveries. Aronnax is fascinated by Nemo's library, collections, instruments, and engineering. Ned considers comfort irrelevant without liberty and begins watching for a chance to escape as the Nautilus starts its submerged journey across the Pacific.

Nemo introduces Aronnax to direct exploration of the sea. Wearing diving suits supplied with air, the party walks across the ocean floor, visits an underwater forest, and hunts marine animals. The Nautilus crosses the Pacific while Aronnax records its life and geography, including the traces of expeditions lost around Vanikoro. In the Torres Strait the submarine runs aground near an island, giving Ned hope of reaching land. Nemo allows the three guests ashore to gather food, but local islanders pursue them back to the vessel and attempt to board. Nemo repels the attack through the Nautilus's electrically protected exterior without abandoning his independence. Soon afterward a crewman is mortally injured. Nemo takes Aronnax, Conseil, and others to a cemetery beneath the sea, where the dead man is buried among coral. The ceremony shows Aronnax that Nemo's detachment from the land does not mean detachment from his own small community.

The Nautilus enters the Indian Ocean. Nemo takes his guests to a rich pearl bed before the normal diving season, where they watch a poor diver working alone. When a shark attacks the man, Nemo intervenes at close range; Ned kills the shark with his harpoon, and Nemo gives the rescued diver a bag of pearls before leaving. The act reveals compassion that sits uneasily beside Nemo's rejection of human society. The submarine continues through the Red Sea. Nemo uses a submerged passage beneath the Isthmus of Suez to enter the Mediterranean without taking the surface route. Aronnax also sees signs that Nemo uses wealth recovered from the sea to aid people engaged in struggles on land. Ned remains focused on escape, but the Nautilus's speed through the Mediterranean denies him a practical opportunity.

Crossing into the Atlantic, Nemo shows Aronnax the wrecks and treasure of Vigo Bay, one source of the wealth that finances the Nautilus and Nemo's causes. The submarine passes the submerged ruins that Aronnax identifies with Atlantis, then reaches a hidden volcanic refuge where the crew obtains material needed for its power. It descends through the Sargasso Sea and into extreme depths, demonstrating both the vessel's strength and the limits of human observation. During a confrontation between whales, Nemo orders the Nautilus into a destructive hunt against sperm whales threatening a group of baleen whales. Ned, who regards whaling as a skilled human pursuit rather than a reason for indiscriminate slaughter, is disturbed by the result. His admiration for the submarine's abilities has not weakened his desire to leave it, while Aronnax is increasingly divided between loyalty to his companions and access to discoveries no scientist has made before.

The Nautilus drives south through ice and reaches open water beyond the Antarctic barrier. Nemo and Aronnax land at the pole, where Nemo claims the region in his own name. On the return journey shifting ice traps the submarine beneath the surface. The crew and prisoners labor together to cut a route free while the breathable air runs dangerously low. They escape only after exhausting effort and resume the voyage around Cape Horn into the Atlantic. Later, giant squid attack the Nautilus. Nemo, his crew, Ned, Aronnax, and Conseil fight them at close quarters on the deck. One crewman is carried away and killed despite Nemo's attempt to save him. The loss deepens Nemo's grief and withdrawal. Ned's determination to escape becomes urgent, and even Aronnax's scientific fascination can no longer conceal the psychological cost and mortal danger of their captivity.

The Nautilus crosses a stormy North Atlantic and passes the site of a historic naval disaster that holds special meaning for Nemo. A modern warship pursues the submarine. Nemo refuses Aronnax's pleas for restraint and uses the Nautilus as a weapon, ramming the ship and watching it sink with its crew. His actions confirm that his withdrawal from civilization is bound to a personal war against forces he associates with oppression and loss. Afterward he retreats into mourning and becomes less accessible. The submarine travels north to the coast of Norway. Ned arranges an escape in the vessel's boat, and Aronnax and Conseil join him. Before they can get clear, the Nautilus is caught in the Maelstrom. Aronnax loses consciousness and wakes in a fisherman's shelter on the Lofoten Islands with Conseil and Ned. The three captives are free and plan to return home. They cannot say whether Nemo and the Nautilus survived, leaving the submarine commander and his secret world beneath the sea unresolved.

In the North Atlantic, Aronnax sees the full violence behind Nemo's hatred of the powers on land. The Nautilus deliberately destroys a pursuing warship, and Nemo withdraws in grief after watching it sink with its crew. The submarine continues north until it reaches the waters off Norway. Ned Land decides that captivity has become intolerable and arranges an escape with Aronnax and Conseil. As they prepare to leave in the Nautilus's boat, the submarine is drawn toward the Maelstrom. Aronnax loses consciousness during the chaos and later wakes with Conseil and Ned in a fisherman's shelter on the Lofoten Islands. All three have survived and regained their freedom, but they do not know whether the Nautilus or Captain Nemo escaped the whirlpool. Aronnax returns able to record the extraordinary voyage, while Nemo's origins, final fate, and judgment on the surface world remain unresolved.