On a passenger ship off the coast of San Francisco, the wealthy intellectual and literary critic (and the book’s narrator) Humphrey Van Weyden is on his way to visit a friend. Suddenly, however, foggy conditions cause the passenger ship to collide with another ship, and Van Weyden’s ship begins to sink. Van Weyden, who can’t swim, is adrift at sea until Wolf Larsen, the captain of a seal-hunting vessel called the Ghost that is headed for hunting grounds in the waters near Japan, stumbles across Van Weyden and brings him aboard his ship.
Van Weyden passes out from exhaustion. When he wakes up, he’s wearing new clothes, and the sailor Johnson and the cook Thomas Mugridge are caring for him. He goes to Wolf Larsen and offers to pay a large sum of money for Wolf to turn the vessel back toward San Francisco. Wolf Larsen, however, refuses the offer, and forces Van Weyden to join the crew of the Ghost as a cabin boy instead.
As a gentleman who hasn’t ever had to work, Van Weyden struggles to adjust to life on the Ghost at first. He is bad at the tasks assigned to him, and soon after starting work, he injures his knee. At one point, however, he happens to be in Wolf Larsen’s room and notices that the fearsome captain has a surprisingly large collection of books, including works by William Shakespeare, Edgar Allen Poe, and Charles Darwin. Darwin in particular seems to be an influence on Wolf Larsen and his methods of leadership—he frequently implements his own version of Darwin’s concept of “survival of the fittest” by pitting crew members against one other or by forcing crew members to undertake dangerous tasks to prove their toughness.
Despite Wolf Larsen’s cruelty, he and Van Weyden have some surprising similarities. Wolf Larsen enjoys discussing philosophy with Van Weyden, even though they disagree on important issues, such as the existence of an immortal soul (Van Weyden believes humans have souls, but Wolf Larsen doesn’t). However, Wolf Larsen’s outbursts of violence and cruelty often follow these periods of friendliness, reflecting Wolf’s temperamental mood.
At one point during stormy weather off the coast of Japan, the ghost encounters a small boat in need of rescue that contains four engineers and a poet named Maud Brewster who is not a sailor and was only traveling for her health. Although Brewster is an unusual presence on the Ghost, where there are no other women, Wolf Larsen seems to enjoy discussing philosophy with her and Van Weyden, at least on days when he’s in a good mood.
During seal-hunting season, Wolf Larsen gets into a competition with his brother, Death Larsen, who has a reputation for being even more ruthless a leader than Wolf. This competition seems to excite Wolf, and after initial aggression from Death, Wolf responds by stealing several of Death’s boats and capturing some of his hunters.
The evening after his victory, Wolf Larsen is in a good mood, but things take a turn when Van Weyden witnesses Wolf assaulting Maud Brewster. This motivates Brewster and Van Weyden to steal a boat and escape. They hope to make it to Japan, but an unfavorable wind pulls them toward an abandoned island that they call Endeavor Island.
Van Weyden and Maud Brewster spend several weeks alone on the island. Their circumstances force them to learn new survival skills, and they bond over the experience. Van Weyden loves Maud Brewster, but he keeps his feelings to himself. One day, Van Weyden is surprised to see that the Ghost has landed off the coast of Endeavor Island.
Van Weyden works up the courage to explore the Ghost and finds that most of its crew is gone—the only person left is Wolf Larsen, who has been marooned after Death Larsen tracked him down and offered better pay to Wolf’s crew. In addition, Wolf Larsen is blind and in failing health. Maud Brewster and Van Weyden hatch a plan to repair the Ghost (which had its sails cut) and escape, but even in his blind, ailing state, Wolf Larsen resists their efforts and tries to stop them.
Ultimately, however, despite Wolf Larsen’s resistance, Van Weyden and Brewster manage to repair the Ghost and use it to escape the island. Though Van Weyden has many opportunities to kill Wolf, he chooses to spare his life. Wolf’s health continues to decline until he is paralyzed and on the verge of death. Wolf remains defiant to his last breath, even when he can barely communicate. He dies from his ailment in the middle of a violent storm, and Van Weyden and Maud bury him at sea. Soon after, a U.S. ship encounters Van Weyden and Brewster and sends over a rescue boat to retrieve them. Before the ship can reach them, Weyden asks to kiss Brewster.
