Pet Sematary is the 17th book published by Stephen King; it was his 15th novel, and the eleventh under his own name. The book was released by Doubleday on 14 November 1983. King calls it one of his darkest novels.
Louis Creed, a doctor from Chicago, moves to a house near the small town of Ludlow, Maine with his family: wife Rachel; their two young children, Eileen ("Ellie") and Gage; and Ellie's cat, Winston Churchill ("Church"). Their neighbor, an elderly man named Jud Crandall, warns Louis and Rachel about the highway that runs past their house; it is used by trucks from a nearby chemical plant that often pass by at high speeds.
Jud and Louis become friends. Since Louis's father died when he was three, his relationship with Jud takes on a father-son dimension. A few weeks after the Creeds move in, Jud takes the family on a walk in the woods behind their home. A well-tended path leads to a pet cemetery (misspelled "sematary") where the children of the town bury their deceased animals, most of them dogs and cats killed by the trucks on the road. A heated argument erupts between Louis and Rachel the next day. Rachel disapproves of discussing death and she worries about how Ellie may be affected by what she saw at the cemetery. It is later explained that Rachel was traumatized by the early death of her sister, Zelda, from spinal meningitis.
Louis has a traumatic experience as director of the University of Maine's campus health service when Victor Pascow, a student who is fatally injured after being struck by an automobile, addresses his dying words personally to Louis even though they have never met. On the night following Pascow's death, Louis is visited by the student's walking, conscious corpse, which leads him to the cemetery and refers specifically to the "deadfall", a dangerous pile of tree and bush limbs that form a barrier at the back. Pascow warns Louis not to "go beyond, no matter how much you feel you need to." Louis wakes up in bed the next morning convinced it was a dream, but discovers his feet and the bedsheets covered with dirt and pine needles. Louis dismisses the episode as a result of stress caused by Pascow's death coupled with his wife's anxieties about death. He accepts the situation as a bout of sleep walking.
Louis is forced to confront death at Halloween, when Jud's wife, Norma, suffers a near-fatal heart attack. Thanks to Louis's immediate attention, Norma recovers. Jud is grateful for Louis's help, and decides to repay him after Church is run over by a truck at Thanksgiving. Rachel and the children are visiting her parents in Chicago, and Louis frets over breaking the news to Ellie. Jud takes him to the pet cemetery, supposedly to bury Church. Instead, Jud leads Louis beyond the deadfall to "the real cemetery": an ancient burial ground that was once used by the Micmacs, a Native American tribe. Following Jud's instructions, Louis buries the cat and constructs a cairn.
The next afternoon, the cat returns home. However, while he used to be vibrant and lively, he now acts strangely and "a little dead," in Louis's words. Church hunts for mice and birds much more often, but rips them apart without eating them. The cat also gives off an unpleasant odor. Louis is disturbed by Church's resurrection and begins to regret his decision. Jud tells Louis about his dog Spot, who was brought back to life in the same manner when Jud was twelve. Louis asks if a person was ever buried in the Micmac grounds, to which Jud answers vehemently no.
Several months later, Gage, who had just learned to walk, is run over by a speeding truck. At Gage's wake, Rachel's father, Irwin, who never respected Louis or his daughter's decision to marry him, berates Louis harshly, blaming Louis for the boy's death. The two fight in the funeral home's viewing room and upset the casket; Rachel witnesses the fight and becomes hysterical.
Overcome with grief and despair, Louis considers bringing his son back to life with the power of the burial ground. Jud, guessing what Louis is planning, attempts to dissuade him by telling him the story of Timmy Baterman, a young man from Ludlow who was killed charging a machine gun nest on the road to Rome during World War II. His father, Bill, put Timmy's body in the burial ground, where he came back to life, and was seen by terrified townsfolk soon thereafter. Jud and three of his friends went to the Baterman house to confront the pair, but Timmy confronted each of them with indiscretions they had committed, indiscretions he had no way of knowing, thus giving the impression that the resurrected Timmy was actually some sort of demon who had possessed Timmy's body. Jud and his friends fled the house horrified, and Bill shot his son and burned his house to the ground, killing himself.
Jud concludes that Gage died because he showed Louis the burial ground. There are hints that at some point the burial ground was used for victims of cannibalism and that it became the haunt of the Wendigo, a terrible creature of the forest, whose mere presence gives men a taste for the flesh of their own kind. In Jud's words the "ground had gone sour" and now corrupts any animal or person buried there.
Despite Jud's warning and his own reservations, Louis's grief and guilt spur him to carry out his plan. Louis has Rachel and Ellie visit her parents in Chicago again, not telling them his intentions, intending to bury Gage and then spend a couple of days with him in private to 'diagnose' his son and determine if what happened to Timmy has happened to him. Louis exhumes his son's body and takes him to the burial site. Along the trail, the Wendigo nearly frightens him away but Louis's determination, combined with the power of the burial site, keeps him moving.
Ellie has a nightmare featuring Victor Pascow on the flight to Chicago. Because of Ellie's near hysteria, and an agreement between Rachel and her daughter as to Louis's behavior, Rachel attempts to fly back to Maine, but misses her connecting flight at Boston and decides to drive the rest of the distance.
Louis buries Gage at the burial ground. Gage returns as a demonic shadow of his former self, able to talk like an adult. He breaks into Jud's house and taunts Jud about his wife's implied infidelity, then kills Jud with one of Louis' scalpels. When Rachel arrives at Jud's house, Gage kills her also (and, it is implied, partially eats her corpse). This event pushes Louis's mind into its final stage of insanity. Louis kills Church and Gage with a fatal dose of morphine, and then grieves for his son by sitting in the corner of the hallway.
Louis, now completely insane and having prematurely aged with shockingly white hair, burns down Jud's house, then carries Rachel's body to the burial ground, saying that he "waited too long" with Gage but is confident that Rachel will come back the same as before. After being interrogated by investigators about the fire, Louis waits until nightfall for Rachel to return. Playing solitaire, he hears his resurrected wife walk into the house, and the novel ends with Rachel speaking "Darling", her mouth sounding as if it is full of dirt.
The story was adapted into a film in 1989.