Addie Bundren, the wife and matriarch of an impoverished southern family, has fallen deathly ill. Her family believes that she is soon to pass. Her eldest son, Cash, begins to use his impressive carpentry skill to build a coffin for his mother right outside her bedroom window. Despite their mothers declining health, Darl and Jewel make plans to leave town to assist their neighbor, Vernon Tull, in making a delivery.
Vernon’s wife and two daughters have been aiding Addie on her death bed. Not long after the boys leave, Addie dies. The youngest of her children, Vardaman, believes that his mother’s death is a result of a fish that he had caught and cleaned earlier that same day. With a bit of help, Cash finishes the coffin just before sun rise. Vardaman is deeply troubled at the sight of his mother being nailed shut in a wooden box.
While the others rest that evening, he drills to holes into the lid, two of which accidently bore through Addie’s face. Dewey Dell, the daughter of Addie and Anse, has recently fallen pregnant by a local farmhand named Lade. She is so overwhelmed by her recent state that she is unable to mourn the loss of her mother. A funeral is held the following day, the women since inside the home while the men stand on the porch and converse.
Darl, who serves as the narrator for most of the first section, returns several days later, along with Jewel, and is alerted to the death of his mother by the presence of buzzards over their house. Upon seeing this, Darl sarcastically reassures Jewel, who is seen as ungrateful and selfish, that his precious horse is still alive. Addie has made her husband promise her that her body will be buried in Jefferson, and he obliges even though the task of transporting her body is far more complicated than simply burying her at home.
Cash, who is suffering from a broken leg, assists the family in lifting the coffin, but Jewel ends up putting it into the wagon on his own. Jewel, refuses, however, to ride in the wagon and instead follows behind the family on his horse. He had purchased the horse by working nights on a neighbor’s land.
On the first evening of their venture, the family stays with a generous and kind local family, who voice their skepticism with the mission the Bundrens have embarked on. As a result of recent flooding ,the main bridges leading over the river have either been flooded or have washed away, forcing the family to turn around and attempt to cross the river on a makeshift ford.
The log is overturned, causing the coffin to be knocked out of the wagon and Cash’s leg to be reinjured. The team of mules the family had been using drowns. The ordeal is witnessed by Vernon Tull, who then helps Jewel to recover the coffin from the river. Together the crew search the river for Cash’s tools.
Mrs. Tull recalls Addie’s unchristian inclination to respect her son more than she respected God. Addie, speaking either from her deathbed or from a leap back in time, recalls events from her life: her loveless marriage to her husband, her affair with Whitfield, the local minister and father of Jewel, and the birth of her other children. Whitfield recalls journeying to the home of the Bundrens to confess his affair to Anse, but never actually confesses.
A local horse doctor resets Cash’s leg, causing Cash to pass out cold. Anse buys a new team of mules by taking a mortgage out on his farm equipment, using the money he had been saving for a new set of false teeth, and also money that Cash had been saving from a new gramophone and trading in Jewel’s horse. The family continues their journey.
While in town, Dewey Dell attempts to purchase a drug that will abort her unwanted baby, but the pharmacist refuses to sell it to her, suggesting that she must marry instead. With cement purchased in town, Darl constructs a cast for Cash’s leg, which only increases his pain.
The Bundren’s spend the night on the Gillespie farm. Darl, who has been skeptical of their journey the entire time, sets fire to the farm in hopes of igniting the coffin and his mother’s corpse. Jewel first rescues the animals and then risks his life to drag out his mother’s coffin. Darl lies across the coffin and sobs.
The following day, the Bundren’s arrive to Jefferson and bury their matriarch. Rather than fight a legal battle for Darl having burnt down the farm, the family claim that he is insane and allow him to be committed to the Jackson mental institution.
Dewey Dell tries once more to buy the abortion drug at the local pharmacy, where the boy working behind the counter lies to her, claiming that he is a doctor and tricks her into exchanging sex for services, and what she soon realizes is not an abortion drug. The next day, the children are met by their father, who has obtained a new set of false teeth, and shamefully introduces them to his new bride – a local woman he had met while borrowing shovels to bury his late wife.