Winston Smith lives in Airstrip One, the ruins of an England ravaged by war, civil conflict, and revolution. A member of the middle class Outer Party, Winston lives in a one-room London apartment on a diet of black bread, synthetic meals and "Victory"-branded gin. Telescreens in every building, along with hidden microphones and cameras, permit the Thought Police to identify anyone who might endanger the Party's régime. Children are indoctrinated to inform on suspected thought criminals, especially their parents.
Winston works at the Ministry of Truth, or "Minitrue", as an editor responsible for historical revisionism. He rewrites records and alters photographs to conform to the state's ever-changing version of the truth, rendering the deleted people "unpersons"; the original documents are incinerated in a "memory hole". Winston becomes fascinated by the true past and tries to learn more about it. In an alcove beside his flat's telescreen where he believes he cannot be seen, he begins writing a journal criticising the Party and its enigmatic leader, Big Brother, which, if discovered by the Thought Police, warrants certain death.
At the Ministry, Julia, a young woman who maintains the novel-writing machines and whom Winston loathes, surreptitiously hands Winston a note confessing her love. Winston realises she shares his loathing of the Party. Winston and Julia begin a love affair, at first meeting in the country, and eventually in a rented room atop an antiques shop in a proletarian neighbourhood of London where they believe they are safe, as the room has no telescreen.
Winston approaches the Inner Party member O'Brien, whom Winston believes is an agent of the Brotherhood, a secret organisation that intends to destroy the Party. After discussion, O'Brien gives Winston "The Book", The Theory and Practice of Oligarchical Collectivism by Emmanuel Goldstein, the publicly reviled leader of the Brotherhood. The Book explains the concept of perpetual war, the true meanings of the slogans WAR IS PEACE, FREEDOM IS SLAVERY, and IGNORANCE IS STRENGTH, and how the régime of the Party can be overthrown by means of the political awareness of the proles.
The Thought Police capture Winston and Julia in their bedroom and deliver them to the Ministry of Love (Miniluv) for interrogation. Mr. Charrington, the shopkeeper who rented the room to them, reveals himself as an officer of the Thought Police. O'Brien is also a Thought Police agent, part of a false-flag operation used by the Thought Police to root out suspected thoughtcriminals. O'Brien tortures Winston with electroshock, showing him how, through controlled manipulation of perception, Winston can "cure" himself of his "insanity" – his manifest hatred for the Party. O'Brien explains the Inner Party's motivation: complete and absolute power, mocking Winston's assumption that it was somehow altruistic and "for the greater good". Winston confesses to crimes he did and did not commit, implicating anyone and everyone, including Julia; but O'Brien understands that Winston has not betrayed Julia as he had not stopped loving her. O'Brien sends him to Room 101 for the final stage of re-education, the most feared room in the Ministry of Love, which contains each prisoner's worst fear. As a wire cage holding hungry rats is fitted onto his face, Winston shouts "Do it to Julia!" thus betraying her.
After being reintegrated into Oceania society, Winston encounters Julia in a park. She reveals that she was also tortured, and each admits betraying the other. Later, Winston, now an alcoholic, sits by himself in the Chestnut Tree Cafe, troubled by memories which he is convinced are false. A news bulletin announces Oceania's "decisive victory" over Eurasian armies in Africa. A raucous celebration begins outside, and Winston imagines himself a part of it. As he looks up in admiration at a portrait of Big Brother, Winston feels he has at least ended his "stubborn, self-willed exile" from the love of Big Brother – a love Winston happily returns.