Chapter I
The scene opens with Mr. Jones, the farmer of the Manor Farms, is drunkenly stumbling off to bed and forgets to lock up the farm buildings. When his bedroom light goes out, all of the farm animals go to the big barn to hear Old Major, a prize boar, make a speech. Knowing that his life will shortly come to an end, Old Major wants to give some advice he has learned over his years to the rest of the farm animals. He tells the animals are born into the world to be slaves, are over worked, not fed enough, and then they are slaughtered when their usefulness runs out. Major then begins to speak about a dream he had the night before about a world where animals run free, well fed, treated with respect and are happy. Old Major pushes the idea to overthrow the humans on the farm, and to make his dream come true. He then gives the animals a rule; whatever walks on two legs is bad, and whatever walks on four legs or has wings is good. He also says that when the animals do overthrow the humans, they must never live in their house, sleep in their beds, wear their clothes, or do any other human like qualities. Major then teaches the animals a song called "Beast of England" and they sing it several times before Mr. Jones fires a shot at the barn thinking a fox got in.
Chapter II
Three nights after his speech to the animals, Major dies. During the next three months, the animals make plans to carry out Old Majors wishes to overthrow the humans. The pigs take responsibility in teaching and organizing the plan, since they are the most clever animals on the farm, especially Napoleon and Snowball. Snowball and Napoleon, with the help of another pig names Squealer, make a philosophy called "Animalism". the animals find it hard to understand at first because they have grown up believing that Mr. Jones is their master. Boxer and Clover, the two cart horses, help the pigs get the other animals ready for revolution. A couple days after, Mr. Jones started drinking a lot and forgot to feed the animals. The cows break into the shed because if being so hungry and the animals begin to eat. When Mr. Jones finds out what has happened, him and his men start to whip the cows to get them out of the shed. The animals begin to get angry and turn on the men, and chase them off of the farm. The animals then destroy everything the humans used on them, chains, whips, halters, and other items. A few days later, the pigs tell the other animals that they have taught themselves how to read with the help of the books they found in the Farm House. Snowball then replaces the with farms name with "Animal Farm" rather than "Manor Farm". Napoleon and Snowball reduce the Animalism principles to seven commandments and write them on the inside of the big barn. With the humans being gone, there is not anyone to milk the cows so Napoleon says he will do it while Snowball leads the animals to being the harvest. When the animals return after the work is done for the day, they notice the milk has disappeared.
Chapter III
The animals harvest all summer long. The pigs found out clever ways for the animals to use the human tools and every animals works to their capability. This is the biggest harvest any farm as ever seen. Boxer works the most, and makes "I will work harder!" his new motto. Benjamin, the stubborn donkey, is the only one to notice that there is no change under the new leaders. The animals being to have Sunday meetings, which starts with the raising of their own flag, then there are debates and new policies are established. During the meetings, Snowball and Napoleon always give the loudest opinions, but they always disagree with each other. By the end of the summer all of the animals could read a little, and the pigs became very good at reading as well as writing. Some of the animals could not memorize the seven commandment written on the barn wall, so Snowball made a saying "Four legs good, two legs bad". Soon after the dogs Bluebell and Jessie have pups, Napoleon volunteers to take care of them. He raises the puppies where they are out of sight from the other animals, in a loft above the harness room. The animals notice that the pigs have been taking all the apples and milk, so Squealer tells them that they need the milk and the apples for their brain because the pigs' work is brain work. He makes it clear that, if the animals don't want Mr. Jones coming back, then the pigs get the milk and apples.
Chapter IV
By the middle of summer, the word of Animal Farm has spread life wild fire across half the country. Farmers in joined farms, Mr. Pilkington and Mr. Fredrick are scared that their animals will try to overthrow them like the animals did on the other farm. Animals everywhere have started singing the song " Beast of England" because of the pigeons Snowball sent. Mr. Jones and some of Mr. Pilkington and Mr. Fredrick men come marching onto the farm in hopes of taking it back. Snowball leads the animals on a ambush on the humans. Bower and Snowball fight fearlessly and the men are defeated quickly. After the battle, Boxer and Snowball get medals for their courageous acts. Later, the animals find Mr. Jones gun in the mud, and make a new policy that it be fired on October 12th which is the anniversary of the Battle of the Cowshed and the anniversary of the Rebellion.
Chapter V
Snowball has many ideas to improve the farm, including one get got from one of Mr. Jones books; a windmill. When Snowballs plans for the windmill are complete, a meeting is held in the big barn to decide whether the animals want to build a windmill or not. Snowball gives a speech about why they should build the windmill, and Napoleon has very little to say about it, which isn't normal. When the animal are ready to vote, Napoleon gives an unusual whimper, and nine dogs coming into the barn and chase Snowball off the farm. After they chase him off the farm, the dogs return to Napoleon's side and he announces that the meetings will only be held for ceremonial purposes only. He also says that the pigs will make all the important decisions from now on. Squealer then begins to tell the animals that Snowball was an enemy.
Chapter VI
Throughout the rest of the year, the animals work extra hard to finish the windmill. Boxer work the hardest, fully committing himself to Animal Farm and doing the work of three horses. By the middle of summer, the animals have managed to break enough stone to begin construction on the windmill. They have enough to eat during this time, and since the human are no longer there they can maintain the farm grounds better. Even though the farm seems to be doing well, they still need things they cannot produce, such as iron, and nails. The pigs start to live in the farm house, and sleep in the humans beds, which is breaking one of the seven commandments. Squealer explains that they must have read the commandment wrong, because it states "No animal shall sleep in a bed with sheets". A storm comes one night and blow off roof tiles, knocks down an elm tree and the flagstaff. In the morning when the animals go to the field, they find that the windmill has been knocked down. Napoleon says that it was Snowballs doings and passes a death sentence on him. He then says that they must rebuild the windmill, and cries " Long live the windmill, long live Animal Farm!"
Chapter VII
Through the cold of the winter the animals worked hard to get the windmill rebuild. By the time January came, they were running short on food. Squealer gave speeches on sacrifice, but some animals needed inspiration of Boxer who works the hardest. Later on, the animals hear that Snowball has been coming to the farm at night, and wrecking the animals hard work. Napoleon says that he can tell that Snowball has been around the farm. Whenever something goes wrong, Snowball is to blame. Four days later, Napoleon suspects there are animals that have alliances with Snowballs, and forces them to confess, with the penalty of death.
Chapter VIII
A couple days later, the animals see that the commandment has been changed from "No animal shall kill any other animal" to "No animal shall kill any other animal without cause". Napoleon now has taken the name of "Leader" and other names the animals have made up for him. A poem has also been written about Napoleon. Napoleon sold a pile of lumber to Mr. Fredrick, but before they can use it Napoleon realizes that the money is fake. Napoleon tells the animals that they should prepare for another battle, and soon after that Mr. Fredrick and a large group of men attack Animal Farm. Mr. Fredrick blows the windmill up with dynamite. The animals attack and drive the men away but many animals are killed. Later that night the pigs find a crate of whiskey, and the animals hear singing from the farm house. The next morning the pigs looked terrible, and the animals thought Napoleon was dying. By that night Napoleon made a full recovery, and the commandment that said "No animal shall drink alcohol" now said "No animal shall drink alcohol to excess".
Chapter IX
The animals struggle to rebuild the windmill. Boxer is still hurt from the attack, but still wants to work. No animal has retired from the farm yet, but Boxer is getting pretty close to the age where he could retire; twelve. There is even less food now so the food ration is reduced even more, except for the pigs and dogs. Four sows have Napoleons piglets, and he wants a school to be build, even though the farm doesn't have enough funds to do so. One day while building the windmill, Boxer's strength gives out. The pigs arrange for Boxer to be sent to a human hospital to recover, but the cart that comes for him is actually a glue makers cart, and he is going to be killed.
Chapter X
Years have passed. Animals have died and aged. The animals have completed the new windmill, and the farm seems to have grown richer, but only the dogs and pigs live well. One day, Squealer takes the sheep to a field and teaches them a new chant. When Squealer comes back, one of the horses sees him walking on two legs. Napoleon is also walking on two legs and he carries a whip, and the sheep start to chant "Four legs good, two legs better!" Napoleon then invites the neighboring farmers over to see the farm and play cards. Some animals walk by a farm house window, and they can no longer tell how are the pigs and who are the humans.