When the Arable family’s hog welcomes a litter of spring piglets, Mr. Arable plans on killing the runt—a weakling who will only “make trouble” for the others. His eight-year-old daughter Fern, however, becomes emotional and distraught at the idea of death and demands Mr. Arable spare the pig. Mr. Arable agrees—on the condition that Fern accept responsibility for the pig, and make sure that he is fed and taken care of.
Fern falls in love with her new “baby” Wilbur, feeding him from a bottle and taking him on carriage rides with her dolls in cool spring afternoons. As spring turns to summer, though, Wilbur grows too big to live in the Arables’ yard, and Fern’s parents suggest she sell the pig to their neighbors and relatives, the Zuckermans. Homer Zuckerman offers Fern six dollars for Wilbur, and she takes the pig to live over on their farm, promising to visit as often as she can.
As Wilbur adjusts to his new life on the farm, he finds himself experiencing a series of highs and lows. He likes his dark, fragrant corner of the barn and enjoys Fern’s frequent visits—but is often bored and lonely, and has trouble making friends with the other barnyard animals. The sheep are snobby, the cows are indifferent, and the goose and gander are busy hatching a nest full of eggs. Wilbur is given to fits of crying and despair, and in the midst of one of these fits one night, he hears a small voice call out to him, promising to be his friend.
In the morning, Wilbur is excited to meet his potential new friends, and runs throughout the barn looking for the source of the voice. He is surprised when he realizes it has come from a common gray barn spider who lives over the barn door. The spider introduces herself as Charlotte, and begins telling Wilbur about herself—and her peculiar eating habits, which include sucking the blood from flies and other small insects. Wilbur is nervous to have such a “bloodthirsty” friend, but grateful to have someone to talk to.
As summer arrives in earnest, Fern and her brother Avery spend more and more time at the Zuckermans’ farm, playing in the barn and the fields beyond. One day, the goose eggs hatch, and seven goslings are born. One egg is a dud, and the goose and gander give it to the cunning hoarder rat Templeton who makes his nest beneath Wilbur’s trough as a kind of peace offering—they warn him never to prey upon their goslings, and he reluctantly agrees to the truce. As Wilbur grows bigger with each passing day, he draws the concern of a kind old sheep who warns him that if he keeps getting fatter, Homer, his wife Edith, and their hired man Lurvy will surely kill him for meat come Christmastime. Charlotte comforts the hysterical Wilbur, assuring him that she will find a way to save his life.
Charlotte schemes day in and day out, and eventually settles on a plan that will save Wilbur—she worries, though, that she doesn’t “have much time” to execute it. As soon as the plan is firm and her mind she sets to work. One morning, when Lurvy comes out to the barn with Wilbur’s breakfast, he spies a “miracle”: the words “SOME PIG!” have been threaded into Charlotte’s web. Lurvy alerts Homer and Edith, who are forced to really consider Wilbur for the first time as they try to discern the meaning of the message—and its source. They agree that he is “some pig.”
As word of the “miracle” spreads throughout town and many visitors descend upon the farm to glimpse it, only Fern knows what’s happening: Charlotte is fooling the “gullible” humans into letting Wilbur live. Charlotte enlists the other animals’ help in coming up with more words to describe Wilbur, so that she can weave more miraculous webs. She chooses as her next word “terrific,” and tires herself out weaving the long and complicated web—but the plan continues to be a success as Homer orders Lurvy to start feeding Wilbur more often and putting fresh, sweet hay into his pen. Homer has decided to take Wilbur to the county fair in September to show him off.
Fern tells her parents the stories and conversations she overhears between the animals over at the barnyard, concerning her mother, Mrs. Arable. Mrs. Arable pays a visit to the town doctor, Dr. Dorian, who assures her that there’s nothing to worry about—Fern will grow up and start playing with the other children in her own time. As summer winds down, Wilbur is the center of attention on the farm: he has grown big and beautiful, and entertains large audiences of people who come to see him and Charlotte’s ever-changing webs. Wilbur is getting excited about the fair, but Charlotte won’t commit to going—she is feeling tired lately, and knows that soon she must build her egg sac.
The night before the fair, everyone is excited and restless—humans and animals alike. Lurvy and Homer dream of the prizes Wilbur will win, while Fern and Avery dream of rides and games. Even Templeton the rat gets excited at the idea of going to a “paradise” full of food scraps and discarded junk. Charlotte has agreed to come, and on the morning of the festivities, she and Templeton scurry into Wilbur’s crate. When the Arables arrive to drive with the Zuckermans out to the fairgrounds, Mr. Arable remarks on how large Wilbur has become, and what great ham and bacon the Zuckermans will get out of him come Christmas. The startled Wilbur faints as he overhears this.
Wilbur recovers, and after the Zuckermans and Arables pack him into his crate, they all head off for the fair. Fern and Avery immediately ask for money so that they can run off and play games, while the adults help Wilbur settle into his temporary pen. Charlotte takes up residence in the eave of a nearby shed, where she spots something upsetting: in the next pen over, there is an incredibly large pig named Uncle. Charlotte is determined, though, to ensure Wilbur takes home first prize anyway, and plans on spinning a web—even though she is “swollen” and “listless,” she remains devoted to saving Wilbur’s life.
That evening, as Fern rides the Ferris wheel with her friend Henry Fussy and Templeton raids the emptying fairgrounds for food and scraps, Charlotte gets to work on her new web: she is going to weave the word “humble,” which she feels describes Wilbur perfectly. As night falls, the exhausted Charlotte starts a new project: she is making something for herself “for a change,” and it is going to be her “masterpiece.”
The next day, Charlotte has finished spinning an egg sac and filling it with over five hundred eggs. As the Arables and Zuckermans arrive at the fair and see the newest web, they are overcome with emotion—but devastated when they see that a blue ribbon has been pinned to Uncle’s pen. Everyone is surprised when a voice over the loudspeaker calls them all to the judges’ stand for a special announcement. As the group hurries Wilbur into his crate and hustles him over to the stand, Fern finds herself wishing she were up on the Ferris wheel again with Henry Fussy.
At the judges’ table, Wilbur is awarded a special prize for his contribution to the success of the county fair and the local economy. Homer is awarded twenty-five dollars, and Wilbur gets a special bronze medal. After the ceremony, Wilbur returns to his pen and asks Charlotte if she’s excited to return to the barn. Charlotte, though, replies that she won’t be going home: she is dying, and has hardly enough strength to move her arms. Wilbur throws himself on the ground, hysterical, but Charlotte urges him to calm down. Wilbur decides that in light of all Charlotte has done for him, there must be one last thing he can do for her: he can bring her egg sac home. He enlists Templeton’s reluctant help in fetching the egg sac down from the eave, and promises in exchange that Templeton can help himself to each of Wilbur’s meals before Wilbur even touches them. Templeton scurries down with the egg sac and drops it at Wilbur’s feet just as the Arables and Zuckermans return to the pen to load Wilbur up. He places the egg sac in his mouth for the journey home, and winks at Charlotte as he leaves. The next morning, she dies alone but in peace.
Back at the barn, life resumes as normal. Wilbur keeps watch over the egg sac and continues to grow larger. Even when winter descends, Wilbur remains happy and calm—he knows that because of Charlotte’s help, his worth has been proved and his life is now safe. Fern and Avery come to the Zuckermans’ to play at Christmastime, but Fern is no longer interested in the barnyard, or Wilbur himself.
Winter turns to spring, and, one morning, hundreds of tiny spiders begin to emerge from Charlotte’s egg sac. Wilbur greets them all excitedly, but they soon launch threads of silk and float away on the warm spring wind. Only three of them stay behind—Wilbur helps them select the names Joy, Aranea, and Nellie, and he tells them all about how wonderful their mother was. Wilbur pledges his friendship to the spiders, and they pledge theirs in return. As the months and years go by, Wilbur lives a long and happy life and meets many of Charlotte’s descendants—but none of them “ever quite [take] her place in his heart.”