Brave New World begins with a tour of the Central London Hatchery and Conditioning Centre, where students (and the reader) are given an idea of the values and processes upon which the World State is built. Here all citizens begin their lives as babies in bottles, bred and grown into a specific caste. Here the babies are decanted – natural birth no longer exists, with the idea of mothers and fathers now taboo - and here the children begin their conditioning. With hypnopaedia and Neo-Pavlovian conditioning all citizens are brainwashed from birth to be satisfied with their lives and positions, to uphold the values of the state, and to never crave anything they cannot have. The students learn that all citizens are discouraged from liking literature and nature, conditioned instead to desire sport, sex and pleasure. The World State is a totalitarian government that has eliminated truth and beauty in favour of stability and happiness.

Huxley then introduces two of his main characters: the beautiful and popular Lenina Crowne, and the awkward and anti-social Bernard Marx. Both belong to the privileged higher castes. Lenina is intrigued by the mysterious Bernard and agrees to take a trip with him to the New Mexico Savage Reservation, Malpais. Before they leave, the Director of the Hatcheries accidentally lets slip to Bernard that he once took a lover to the reservation, but she became lost there and he never saw her again. The Director, annoyed with himself for sharing this information, makes it clear that Bernard’s job is threatened unless he can learn to conform.

At Malpais, a shock awaits Bernard and Lenina. While they are watching a traditional Zuni religious ceremony, a white man named John introduces himself. He explains that his mother was a woman from the World State who became lost in the reservation many years ago. John has been brought up in the reservation, learning about the new world from his mother, while looking to the Zuni culture and the works of Shakespeare for his moral lessons. Bernard quickly works out that John must be the son of the Director, and sees his chance for revenge. He invites John and his mother Linda to return to London with them.

In London, Bernard presents Linda and John to the Director, humiliating him in front of the entire Hatchery workforce. While the Director is forced to resign, Bernard finds that he has gained a new popularity from his association with John ‘the Savage’, whom all of London is desperate to meet. He introduces John to his friend Helmholtz, who also expresses dissatisfaction about life in the World State. John is whisked around London, meeting dignitaries and V.I.P.s, and learning about the marvels of the new world. However, John responds to these sights with astonishment and disgust, seeing moral degeneracy at every step and turning to Shakespeare for comfort. When Lenina, who John harbours strong feelings for, offers herself to him, John can only react with scorn and anger.

Meanwhile, John’s mother Linda lies in a stupor, steadily killing herself with the pleasure-drug soma. Her death is the last straw for John. He attempts to free the lower castes by throwing away their soma, but is caught up in a riot and quickly arrested. Bernard, Helmholtz and John are all taken to meet Mond, the World Controller, who explains that truth, passion and beauty are worth sacrificing in the pursuit of happiness. He decides that Helmholtz and Bernard must be exiled to an island so that they cannot spread dissatisfaction with their radical ideas. John, however, must stay, as Mond wishes to observe his behavior and reactions further.

John, not wishing to be a part of the new world, retreats to an isolated spot in the English countryside, where he sets up residence in a lighthouse. He spends his days growing food, reflecting on religion and morality, and performing acts of self-abasement to atone for sinful thoughts. However, John finds that he cannot easily escape from the new world. Swarms of reporters and interested citizens arrive to see his strange acts of self-flagellation. When Lenina turns up, desperate for his affection, John angrily begins to whip her. The crowd is thrilled by this interaction, and before he knows it, John has been drawn into a huge orgy. The following morning, realizing that he has betrayed his values and sinned so despicably, he commits the ultimate act of penance or despair. When a new batch of adoring fans arrive at the lighthouse, they find that John has hanged himself.