Manor Farm is a former prosperous farm that has fallen on hard times, and suffers under the now ineffective leadership of its drunken and aggressive owner, Mr. Jones. One night, Old Major, the prize boar and the second-oldest on the farm, calls the animals on the farm for a meeting, where he compares the humans to parasites and encourages them to break free from their tyrant's influence, while reminding them that they must hold true to their convictions after they have gained freedom. With that, he teaches the animals a revolutionary song, "Beasts of England", before collapsing dead mid-song to the animals' horror.The next morning, Jones neglects to feed the animals for breakfast, and they decide to break into the storehouse to help themselves. When Jones wakes up and attempts to intimidate them with his whip, the animals revolt and drive the drunken and irresponsible Mr. Jones from the farm, renaming it "Animal Farm". They set to work destroying every trace of Jones' influence, mainly the weapons used against them. An investigation of the farmhouse leads them to concede against living there, though one of the head pigs, a boar named Napoleon, who is the film's antagonist, takes interest in the abandoned house, and even more so in a litter of puppies left motherless.The Seven Commandments of Animalism are written on the wall of a barn to illustrate their community's laws. The most important is the seventh, "All animals are equal." All the animals work, but the workhorse, Boxer, and his friend Benjamin, the young donkey and the film's protoganist, put in extra work. A young pig named Snowball attempts to teach the animals reading and writing; food is plentiful, and the farm runs smoothly. The pigs elevate themselves to positions of leadership and set aside special food items, ostensibly for their personal health. Napoleon takes the pups and trains them privately.When Snowball announces his idea for a windmill, Napoleon opposes it. Snowball makes a speech in favor of the windmill, whereupon Napoleon has his dogs chase Snowball away. In Snowball's absence, Napoleon declares himself leader and makes changes. Meetings will no longer be held and instead a committee of pigs will run the farm. Using a young pig named Squealer as a mouthpiece, Napoleon spurs the animals into setting forth his regime. The animals work harder with the promise of easier lives with the windmill.Napoleon abuses his powers, making life harder for the animals; the pigs impose more control while reserving privileges for themselves. During this time, the pigs also decide to start altering their own laws. "No animal shall sleep in beds" is changed to "No animal shall sleep in beds with sheets" when the pigs are discovered to have been sleeping in the old farmhouse. "No animal shall drink alcohol" is changed to "No animal shall drink alcohol to excess" when the pigs discover the farmer's whisky. Despite this, most animals keep believing that the pigs are acting in the best interest of all animals.Before long, Napoleon's greed drives him to negotiate with a local trader named Mr. Whymper for a supply of jellies and jams. The price is all the hens' eggs. When the hens discover this, they attempt to revolt by throwing their eggs at the pigs during an attempted seize by force. To instill fear, Napoleon not only puts the hens at the hands of the pig committee, but also selects a duck and sheep to be false accused of treachery. They are taken outside and murdered by the dogs, with their blood used to edit a commandment regarding killing to being legal "with cause". "Beasts of England" is banned as inappropriate, as according to Napoleon, the dream of Animal Farm has been realized.Growing jealous of Whymper's financial success due to his trading with Animal Farm, a hostile group of farmers attacks the farm, and Jones, who was denied the chance to rejoin them, uses blasting powder to blow up the windmill with himself inside. Though the animals win the battle, they do so at great cost, as many, including Boxer, are wounded. Boxer continues working harder and harder, until he collapses one night while working on the windmill. Napoleon sends for a van to take Boxer to a vetinarian. Benjamin notices that the van belongs to Mr. Whymper's glue factory, and attempts to mount a rescue. However, his attempts are futile and Boxer is taken away, presumably to his death. Squealer delivers a phony speech, claiming to have been at Boxer's side at his deathbed, and his last words being to glorify Napoleon. He also dismisses any claim that Boxer was sold in exchange for money. The hurt animals fully realize that Boxer's death was planned simply to promote further loyalty to Napoleon's dictatorship, but are sent away by the snarling dogs.Years pass, and the pigs now have learned to walk upright and wear clothes. Napoleon now dresses in a suit with medals (a reference to Nikita Khrushchev). The Seven Commandments are reduced to a single phrase: "All animals are equal, but some animals are more equal than others." Napoleon holds a dinner party for a delegation of outside pigs, who congratulate Napoleon on having the hardest-working animals in the country on the least feed. Napoleon gives a toast to when pigs own and operate farms everywhere.Benjamin, overhearing the conversation, imagines the faces of the pigs changing into the face of Mr. Jones. Realizing that things have become "worse then ever for ordinary creature", all of the animals unite together to overthrow Napoleon. The film closes with a smashed portrait of Napoleon as he is being overwhelmed by the animals and beaten to death.