London, chief province of Oceania, the future, 1984. Atomic war and famine has resulted in the collapse of civilisation and the formation of a new totalitarian regime. The Party, led by the all-seeing presence of Big Brother, regiments life for its citizens. Winston Smith, an Outer Party member, works in the Ministry of Truth, amending archive newspaper reports in line with Big Brother's latest pronouncements and developments in the state's interminable war.

Along with other Party members, Winston views announcements by Big Brother on a 'telescreen', featuring propaganda messages of productivity and news on the war. While attending the Two Minutes Hate, at which hysterical hatred is whipped up against the state's enemies, Winston first sees Julia, a woman wearing the sash of the Anti-Sex League. Secretly, Winston's hatred is for Big Brother. In the canteen afterwards, his colleague Syme explains how the Party is developing the 'newspeak' language by destroying words, primarily those needed to articulate dissent. Winston again spots Julia nearby.

In his dilapidated flat, Winston starts a diary before he is asked to help his neighbours, the Parsons, with a plumbing problem. Parsons' children, spies for the Party's Youth League, accuse him of being a traitor. Later, Winston manages to hide from the view of the telescreen in a secret corner of his room. He writes his diary, expressing his distaste for the Party's dictatorial rule.

Winston visits a bar in a prole sector of the city. Befriending an old man, he questions him about life before the revolution and learns that the Party's description of it is distorted. He visits an antiques shop and buys an ornament. The shop's owner, Charrington, shows him the room above, which lacks a telescreen. He hides briefly when he sees Julia watching him from the door.

Winston stops at a café and has a drink with Syme. Syme reports that his conduct is under investigation, breaks down and is taken away by the Thought Police.

Julia operates the 'pornorite' machine at the Ministry of Truth, churning out automated erotica for consumption by the proles. She contrives a minor injury to enable her to pass by Winston's work cubicle. She drops a note on his desk stating that she loves him. Sitting next to each other at the next mealtime, they arrange a secret rendezvous, away from the watchful eye of Big Brother.

In the privacy of the countryside, they kiss and embrace, acknowledging that their actions will eventually be discovered. Winston tells Julia that he separated from his wife because she regarded their marriage solely as a declaration of support for the Party.

Winston rents Charrington's upstairs room, so that the lovers can meet regularly. During 'hate week', they avoid the street parades by hiding in their room. Terrified by the sight of a rat, Winston is reminded of a painful memory from his childhood, when he discovered his baby sister had been attacked by rats in her cot.

Winston and Julia meet with a party member, O'Brien, who provides them with a book, outlining the ways in which the party can be destroyed. They agree to join the rebellious 'Brotherhood' and act against the regime.

Later, in their rented room, a secret telescreen reveals that Winston and Julia's rebellion is known to Big Brother. The Thought Police storm in and arrest the lovers. Charrington reveals himself to be their agent.

Imprisoned in the Ministry of Love, Winston encounters Parsons, who has been arrested for 'thought-crime'. He proudly admits that his own daughter denounced him. Winston is tortured by O'Brien, who was a double agent for Big Brother all along. Winston willingly confesses to all manner of crimes but nevertheless is tortured to force him to accept the untruths that underlie the Party's control.

In 'Room 101', Winston is confronted with his own personal demons - the prospect of attack by rats. After seven weeks of imprisonment and torture, he finally fully succumbs and in his terror betrays Julia.

Later, after his release, he sees Julia in a café. The former lovers admit betraying each other and acknowledge that their feelings have gone. As the telescreen announces victory in war, Winston is overwhelmed with love for Big Brother.