Wilfred owns eighty acres of farmland which have been in his family for generations. His wife owns an adjoining one hundred acres willed to her by her father. Wilfred loves his farm and scorns the thought of living in a city, but Arlette is discontent with farm life and wants to move to Omaha. She plans to divorce Wilfred and sell her land to a livestock company for use as a slaughterhouse. Wilfred, who is very attached to the land, can't stand to let it be used in such a way and manipulates his reluctant fourteen-year-old son, Henry, into helping him murder his own mother.
The two get Arlette drunk, during which she makes several crude remarks about Henry's girlfriend, Shannon Cotterie, angering the boy enough to commit to Wilfred's plot. After they take Arlette to bed, Wilfred brutally slashes her throat with a butcher knife, killing her. He and Henry then dump the body in a well behind the barn. Later, as Wilfred dumps a blood-soaked mattress into the well with Arlette, he notices that her body has become infested with rats.
Wilfred decides to fill in the well to hide the body, but knows that doing so will arouse suspicion. He purposefully has one of his aged cows fall in the well to provide a cover story for filling it in. Right afterwards, the local sheriff—acting on behalf of a lawyer for the livestock company—searches Wilfred's farmhouse to look for Arlette, but finds nothing suspicious. Wilfred and Henry finish burying the cow (and Arlette) in the well, but one of the rats crawls out of the soil. Henry kills the rat, thinking it is a sign that Arlette is haunting them.
One night, in the barn, Wilfred encounters a rat as it attacks one of his other cows, severing one of her teats. A few months later, Henry—whose personality has eerily changed since the murder—impregnates Shannon. This sours the friendship between Wilfred and Shannon's father, Harlan, a neighboring farmer. Shannon is sent to a Catholic girls' school in Omaha, but Henry flees to bail her out, committing several robberies along the way. After he succeeds, Henry and Shannon begin a publicized career as a duo of Bonnie and Clyde-style bank robbers called the "Sweetheart Bandits", becoming wanted in several states.
Wilfred becomes emotionally destitute in Henry's absence. He again encounters the rat found in the barn, a seeming impossibility due to the fact that he blocked the well pipe he thought the creature has come from. The rat bites his hand and causes it to become severely infected with gangrene, necessitating its amputation. Soon after, Wilfred claims that Arlette's living corpse—accompanied by a large group of rats—leaves the confines of the well and enters the farmhouse, confronting him. Arlette gives him a detailed premonition of the violent demises of Henry and the still-pregnant Shannon in Nevada.
When Arlette's prophecy comes true, Wilfred tries to sell the land parcel he killed her for. However, Harlan and the townspeople, all disgusted with Wilfred, refuse to help him. He is forced to leave Hemingford Home as a pariah, after being forced to sell the land to the livestock company. He moves to Omaha and spends the first two years visiting the scenes of Henry's crimes and drinking away the money he received from selling the land. He finds two jobs as a garment factory worker and a librarian. He quits both, he claims, when the rats begin to stalk him again.
At the conclusion, Wilfred sits in a hotel room in Omaha, telling the reader that Arlette's rats are there and eagerly waiting for him to finish, so that they can devour him. He also claims to hear the spectral footsteps of Arlette, Henry, and Shannon in the hallway. Wilfred writes that he plans to shoot himself before the rats consume him, signifying a final victory against Arlette. However, his writing indicates that the gun is somehow misplaced and he is eaten alive by the rats before he can find it.
The story ends with a newspaper clipping about Wilfred's death. The article states that Wilfred was found with bite marks – which the hotel's Chief of Security assumes are self-inflicted – all over his body, including his wrists. This leaves the reader to speculate about whether Wilfred's account was true or the delusions of a half-mad psychotic.