and
Édouard Riou In 1866 ships of various nationalities sight a mysterious
sea monster, which is speculated to be a gigantic
narwhal. The
United States federal government assembles an expedition in
New York City to find and destroy the monster. Professor Pierre Aronnax, a French
marine biologist and the story's
narrator, is in town at the time and receives a last-minute invitation from the
U.S. Government to join their expedition to find said monster. A Canadian
whaler and master
harpooner named Ned Land and Aronnax's faithful manservant, Conseil, are also among the participants. The expedition leaves Brooklyn aboard the
United States Navy frigate Abraham Lincoln, captained by
Admiral Farragut. The ship travels south around
Cape Horn into the
Pacific Ocean. After a five-month search ending off
Japan, the frigate locates and attacks the monster, which damages the ship's rudder. Aronnax and Land are hurled into the sea, and Conseil jumps in after them. They survive by climbing onto the "monster", which, they are startled to find, is a futuristic submarine. They wait on the deck until morning, when they are captured and introduced to its mysterious constructor and commander,
Captain Nemo. The rest of the novel describes the protagonists' adventures aboard the submarine
Nautilus, which was built in secrecy and now roams the seas, beyond the reach of governments. In self-imposed exile, Captain Nemo seems to have a dual motivation—a quest for scientific knowledge and a desire to escape terrestrial
civilisation. Nemo explains that his submarine is
electrically powered and can conduct advanced marine research; he also tells his new passengers that his secret existence means he cannot let them leave—they must remain on board permanently. They visit many oceanic regions, some real and others fictional. The travellers view
coral formations, sunken vessels from the
Battle of Vigo Bay, the
Antarctic ice barrier, the
transatlantic telegraph cable and the legendary underwater realm of
Atlantis. They even travel to the
South Pole and are trapped in an upheaval of an iceberg on the way back, caught in a narrow gallery of ice from which they are forced to dig themselves out. The passengers also put on
diving suits, hunt
sharks and other marine
fauna with air guns in the underwater forests of Crespo Island and attend an undersea funeral for a crewman who died during a mysterious collision experienced by
Nautilus. When the submarine returns to the
Atlantic Ocean, a school of
giant squid ("devilfish") attack it and kill another crewman. The later pages suggest Captain Nemo went into undersea exile after his homeland was conquered and his family were slaughtered by a powerful
imperialist nation. Following the episode of the devilfish, Nemo largely avoids Aronnax, who begins to side with Ned Land. Ultimately,
Nautilus is attacked by a
warship from the mysterious nation that has caused Nemo such suffering. Carrying out his quest for revenge, Nemo—whom Aronnax dubs an "
archangel of hatred"—rams the ship below its waterline and sends it to the bottom, much to the professor's horror. Afterwards, Nemo kneels before a portrait of his deceased wife and children, then sinks into a deep depression. Circumstances aboard the submarine change drastically: watches are no longer kept, and the vessel wanders about aimlessly. Ned becomes so reclusive that Conseil fears for his wellbeing. One morning, he announces that they are in sight of land and have a chance to escape. Aronnax is more than ready to leave Captain Nemo, who now horrifies him, yet he is still drawn to the man. Fearing that Nemo's very presence could weaken his resolve, he avoids contact with him. Before their departure, the professor eavesdrops on Nemo and overhears him calling out in anguish, "O almighty God! Enough! Enough!" Aronnax immediately joins his companions as they carry out their escape plans, but as they board the submarine's
skiff they realise
Nautilus has seemingly blundered into the ocean's deadliest
whirlpool, the
Moskstraumen (more commonly known as the Maelstrom). They escape and find refuge on an island off the coast of Norway. The submarine's ultimate fate remained unknown until the events of
The Mysterious Island (1875). ==Themes and subtext==