The narrator begins by describing his childhood in California’s Salinas Valley, where he learned to tell east from west by looking at the mountains—the bright Gabilan Mountains to the east and the dark Santa Lucia Mountains to the west. The valley’s weather comes in thirty-year cycles: five or six years of heavy rainfall, six or seven years of moderate rainfall, and then many years of dryness. The valley was settled by three peoples: first, the Indians, whom the narrator derides as lazy; next, the Spanish, whom the narrator calls greedy; and finally, the Americans, who the narrator says are even greedier than the Spanish.
In 1870, Samuel and Liza Hamilton—the narrator’s grandparents—arrive in the Salinas Valley from Ireland. The Hamiltons are forced to settle on the driest and most barren land in the valley, as all the better lots are already taken. To support his nine children, Samuel works as a blacksmith, a well-digger, and an unlicensed doctor.
Some time after Samuel Hamilton arrives, a man named Adam Trask settles a fertile corner of the Salinas Valley for himself and lives as a wealthy man. After introducing Adam, the narrator jumps back in time to tell the story of Adam’s childhood.
Adam is the son of Cyrus Trask, a conniving Connecticut farmer who loses a leg in the Civil War and then passes on syphilis to his wife after contracting it from a black prostitute in the South. Cyrus’s pious wife commits suicide shortly after discovering her illness. Cyrus needs help with the children, so he marries a young woman named Alice, who lives in fear of her husband and even hides her tuberculosis from him out of worry that he might impose a harsh medical treatment upon her. In his spare time, Cyrus studies military history and strategy so that he might create convincing lies about his time in the Army. His lies about his alleged heroics in the Civil War gain him widespread respect and ultimately an appointment as Secretary of the Army.
As a boy, Adam Trask is kind and good-natured, but his half-brother, Charles, is boisterous and aggressive. One day, Charles beats Adam severely simply because Adam defeats him in a game. Adam loves his stepmother, Alice, and anonymously leaves her secret gifts in order to make her smile.
When Adam is a young man, Cyrus tries to convince him to go into the Army. When Adam asks his father why he does not want Charles to go into the army instead, Cyrus responds that the army would cultivate a part of Charles’s nature that needs to be suppressed. In addition, Cyrus says that he loves Adam better.