Ishmael is a schoolmaster who often feels that he must leave his quiet existence and go to sea. Much of his life has been spent as a sailor, and his voyages are a means of ridding himself of the restlessness that frequently seizes him. One day, he decides that he will sign on a whaling ship, and packing his carpetbag, he leaves Manhattan and sets out, bound for Cape Horn and the Pacific.
On his arrival in New Bedford, Ishmael goes to the Spouter Inn near the waterfront to spend the night. There he finds he can have a bed only if he consents to share it with a harpooner. His strange bedfellow frightens him when he enters the room, for Ishmael is certain that he is a savage cannibal. After a few moments, however, it becomes evident that the native, whose name is Queequeg, is a friendly person, for he presents Ishmael with an embalmed head and offers to share his fortune of thirty dollars. The two men quickly become friends and decide to sign on the same ship.
Eventually they sign on the Pequod, a whaler out of Nantucket, Ishmael as a seaman, Queequeg as a harpooner. Although several people seem dubious about the success of a voyage on a vessel such as the Pequod, which is reported to be under a strange man, Captain Ahab, neither Ishmael nor Queequeg has any intention of giving up their plans. They are, however, curious to see Captain Ahab.
For several days after the vessel has sailed, there is no sign of the Captain, as he remains hidden in his cabin. The running of the ship is left to Starbuck and Stubb, two of the mates, and though Ishmael becomes friendly with them, he learns very little more about Ahab. One day, as the ship is sailing southward, the Captain strides out on deck. Ishmael is struck by his stern, relentless expression. In particular, he notices that the Captain has lost a leg and that instead of a wooden leg, he now wears one cut from the bone of the jaw of a whale. A livid white scar runs down one side of his face and is lost beneath his collar, so that it seems as though he were scarred from head to foot.
For several days, the ship continues south looking for whale schools. The sailors take turns on masthead watches to give the sign when a whale is sighted. Ahab appears on deck and summons all his men around him. He pulls out a one ounce gold piece, nails it to the mast, and declares that the first man to sight the great white whale, known to the sailors as Moby Dick, would get the gold. Everyone expresses enthusiasm for the quest except Starbuck and Stubb, Starbuck especially deploring the madness with which Ahab has directed all his energies to this one end. He tells the Captain that he is like a man possessed, for the white whale is a menace to those who would attempt to kill him. Ahab lost his leg in his last encounter with Moby Dick; he might lose his life in the next meeting, but the Captain does not listen to the mate’s warning. Liquor is brought out and, at the Captain’s orders, the crew drinks to the destruction of Moby Dick.
Ahab, from what he knows of the last reported whereabouts of the whale, plots a course for the ship that will bring it into the area where Moby Dick is most likely to be. Near the Cape of Good Hope, the ship comes across a school of sperm whales, and the men busy themselves harpooning, stripping, melting, and storing as many as they are able to catch. When the ship encounters another whaling vessel at sea, Captain Ahab asks for news about the white whale. The captain of the ship warns him not to attempt to chase Moby Dick, but it is clear by now that nothing can deflect Ahab from the course he has chosen.
Another vessel stops them, and the captain of the ship boards the Pequod to buy some oil for his vessel. Captain Ahab again demands news of the whale, but the captain knows nothing of the monster. As the captain is returning to his ship, he and his men spot a school of six whales and start after them in their rowboats. While Starbuck and Stubb rally their men into the Pequod’s boats, their rivals are already far ahead of them. The two mates, however, urge their crew until they outstrip their rivals in the race, and Queequeg harpoons the largest whale.
Killing the whale is only the beginning of a long and arduous job. After the carcass is dragged to the side of the boat and lashed to it by ropes, the men descend the side and slash off the blubber. Much of the body is usually demolished by sharks, who stream around, snapping at the flesh of the whale and at each other. The head of the whale is removed and suspended several feet in the air, above the deck of the ship. After the blubber is cleaned, it is melted in tremendous try-pots and then stored in vats below deck.
The men are kept busy, but their excitement increases as their ship nears the Indian Ocean and the probable sporting grounds of the white whale. Before long, they cross the path of an English whaling vessel, and Captain Ahab again demands news of Moby Dick. In answer, the captain of the English ship holds out his arm, which from the elbow down consists of sperm whalebone. Ahab demands that his boat be lowered at once, and he quickly boards the deck of the other ship. The captain tells him of his encounter and warns Captain Ahab that it is foolhardy to try to pursue Moby Dick. When he tells Ahab where he had seen the white whale last, the captain of the Pequod waits for no civilities but returns to his own ship to order the course changed to carry him to Moby Dick’s new feeding ground. Starbuck tries to reason with the mad Captain, to persuade him to give up this insane pursuit, but Ahab seizes a rifle and in his fury orders the mate out of his cabin.
Meanwhile, Queequeg has fallen ill with a fever. When it seemed almost certain he would die, he requests that the carpenter make him a coffin in the shape of a canoe, according to the custom of his tribe. The coffin is then placed in the cabin with the sick man, but as yet there is no real need for it. Queequeg recovers from his illness and rejoins his shipmates. He uses his coffin as a sea chest and carves many strange designs upon it.
The sailors had been puzzled by the appearance early in the voyage of the Parsee servant, Fedallah. His relationship to the Captain cannot be determined, but that he is highly regarded is evident. Fedallah prophesies that the Captain will die only after he has seen two strange hearses for carrying the dead upon the sea, one not constructed by mortal hands and the other made of wood grown in America. He also says that the Captain himself will have neither hearse nor coffin for his burial.
A terrible storm arises one night. Lightning strikes the masts so that all three flame against the blackness of the night, and the men are frightened by this omen. It seems to them that the hand of God is motioning them to turn from the course to which they had set themselves and return to their homes. Only Captain Ahab is undaunted by the sight. He plants himself at the foot of the mast and challenges the god of evil, which the fire symbolizes for him. He vows once again his determination to find and kill the white whale.
A few days later, a cry rings through the ship. Moby Dick has been spotted. The voice is that of Captain Ahab. None of the sailors, alert as they had been, had been able to sight the whale before their captain. Boats are lowered and the chase begins, with Captain Ahab’s boat in the lead. As he is about to dash his harpoon into the side of the mountain of white, the whale suddenly turns on the boat, dives under it, and splits it into pieces. The men are thrown into the sea, and for some time the churning of the whale prevents rescue. At length, Ahab orders the rescuers to ride into the whale and frighten him away, so he and his men could be rescued. The rest of that day is spent chasing the whale, but to no avail.
The second day, the men start out again. They catch up with the whale and bury three harpoons into his white flanks, but he so turns and churns that the lines become twisted, and the boats are pulled every way, with no control over their direction. Two of them are splintered, and the men hauled out of the sea, but Ahab’s boat has not as yet been touched. Suddenly, it is lifted from the water and thrown high into the air. The Captain and the men are quickly rescued, but Fedallah is nowhere to be found.
When the third day of the chase begins, Moby Dick seems tired, and the Pequod’s boats soon overtake him. Bound to the whale’s back by the coils of rope from the harpoon poles, they see the body of Fedallah. The first part of his prophecy had been fulfilled. Moby Dick, enraged by his pain, turns on the boats and splinters them. On the Pequod, Starbuck watches and turns the ship toward the whale in the hope of saving the Captain and some of the crew. The infuriated monster swims directly into the Pequod, shattering the ship’s timbers. Ahab, seeing the ship founder, cries out that the Pequod—made of wood grown in America—is the second hearse of Fedallah’s prophecy. The third prophecy, Ahab’s death by hemp, is fulfilled when rope from Ahab’s harpoon coils around his neck and snatches him from his boat. All except Ishmael perish. He is rescued by a passing ship after clinging for hours to Queequeg’s canoe coffin, which had bobbed to the surface as the Pequod sank.