Captain "Wolf" Larsen, the absolute master of a seal schooner, is a mystic and philosopher, though he rules his men with an iron hand. On a ferry going from San Francisco to Oakland, Van Weyden, a critic, and Maud Brewster, a novelist, meet in masquerade costumes and are forced overboard when their boat collides with a steamer. Humphrey, then Maud, are picked up by Larsen's crew. Because of her costume, Maud is taken for a boy and placed in the custody of Mugridge, the cook, who attempts to attack her upon discovering her identity. Larsen takes her under his protection and decides to marry her; but as the ceremony begins, the crew mutinies, and Larsen is stricken with blindness as he faces the rebels. The ship is set afire, and though Humphrey and Maud are rescued by another steamer, Larsen, deserted by his crew, refuses to quit his ship and is enveloped in flames.
