Arthur Gordon Pym recounts his experiences at sea, explaining that he was convinced to do so by his friend Edgar Allan Poe.
Pym, the son of a prosperous Nantucket merchants, dreams of sailing adventures. One night, while drunk, Pym’s friend Augustus convinces Pym to take his small boat, the Ariel, out to sea. The duo quickly lose control of the boat in a storm and are only saved when the Ariel is hit and destroyed by a large whaler, the Penguin, whose crew fish them out of the ocean. Pym and Augustus return to Nantucket by morning and are able to pass their haggard appearances off as hangovers.
Augustus joins his captain father, Mr. Barnard, onboard the whaling ship Grampus, but Pym’s grandfather Mr. Peterson forbids him from going. Augustus devises a plan for Pym to stow away in the hold until they are far enough from Nantucket that Mr. Barnard will just have to accept Pym’s presence onboard.
Trapped in the dark, airless hold, Pym loses track of time. His supply of food and water begins to run out and he worries that something is preventing Augustus from reaching him. Pym is surprised to find his dog, Tiger, who has a note tied to him—but who also chews up Pym’s last candles. Pym is able to use the phosphorus from matches to read part of the note: a dire warning urging him to stay hidden. Tiger goes mad from lack of food and air and attacks Pym, who is able to trap him in a box. Pym downs a liquor bottle and smashes it in despair, and the noise attracts Augustus, who has finally come to rescue him from the hold.
Augustus explains that a mutiny has taken place. Led by the first mate and the cook, the mutineers kill most of the crew, only sparing Augustus because one of them, Dirk Peters, takes Augustus under his wing. The mutineers argue amongst themselves about continuing to the South Pacific or turning to piracy in the Caribbean; Peters supports the former plan but is increasingly alone in his position. Peters suspects the first mate is killing his other opponents after one mutineer dies of drinking—or poison—and asks Augustus for support taking over the ship. Augustus tells him about Pym, and they devise a plan together. Pym disguises himself as the body or ghost of the poisoned sailor, and Peters and Augustus use the surprise and confusion this disguise creates amongst the other mutineers to kill all of them except Richard Parker, though Augustus is badly wounded.
Suddenly the Grampus is caught in a terrible storm, so the survivors free Parker to help them save the ship. By the end of the storm the ship is a useless hulk, and the survivors drift without food or water. One day they think they are being rescued, only to encounter a plague ship full of rotting bodies. Parker suggests that they only have one option now to survive: cannibalism. Pym is strongly opposed, but the others outvote him, and they draw straws to determine who will be eaten. Parker draws the shortest straw, and Pym, Peters, and Augustus kill and eat him. Pym and Peters are later able to cut into the waterlogged ship and find some food, prolonging their survival, but Augustus dies of his badly infected wounds. Pym and Peters are finally rescued by the Jane Guy, bound for the Antarctic Ocean.
The Jane Guy stops at several islands before heading due south. An ever-stronger current pulls the ship to the south, and the crew find strange, unrecognizable animals on icebergs and in the water. Eventually the ice thins out and the weather becomes milder, and they reach a wooded, inhabited island. Coming ashore, the crew encounter a large group of heavily armed native people.
The leader of the native people, Too-wit, welcomes the crew and eagerly explores the Jane Guy. He then takes them to his village, Klock-klock. The island impresses Pym with its strangeness and unfamiliarity, but he remains suspicious of the native people. The ship’s captain, Captain Guy, is quickly disarmed by Too-wit’s friendliness and the bountiful resources on the island that he hopes to harvest and trade. After a few weeks the ship will continue south, but first Too-wit invites the crew to a goodbye ceremony. Walking through a ravine to the village, Pym and Peters are distracted by some plants in a side path and barely escape a massive landslide that kills the rest of the crew. Crawling through the narrow crack in the rocks ahead, they emerge on top of a hill and realize that the landslide was deliberate: the native people have using large wooden stakes to cave the side of the hill in. They then observe as the native people attack the Jane Guy and overwhelm the remaining crew members, attacking the ship until the gunpowder onboard causes a massive, destructive explosion.
Pym and Peters stay hidden but struggle to survive on the hilltop, which they cannot find any way down from. Exploring some caves, they find strange markings which Peters insists are writing, but Pym is convinced they are natural patterns. Eventually they decide to scale the cliff face. Surprised and then pursued by the native people, Pym and Peters take a native hostage and steal a canoe, escaping the island and following the current south. Their prisoner, Nu-nu, tells them about the island, which is named Tsalal, but becomes increasingly distressed as they approach the Pole and soon dies.
Nearing the Pole, the current becomes extremely strong, and Pym thinks he sees some kind of waterfall—the air and water are also both extremely warm too. Entering the waterfall, Pym and Peters are struck by the sight of a gigantic white figure in the distance.
A note explains that Pym died in an accident which also destroyed the final chapters of his book. Peters is alive but cannot be contacted to confirm his story. Edgar Allan Poe also observes that the markings on Tsalal do in fact closely resemble letters, which only deepens the mystery of the island.