The events of Cujo take place in Stephen King's novel Cujo, the 1981 horror story about a rabid Saint Bernard.
The novel is set in Castle Rock, Maine, where Cujo belongs to mechanic Joe Camber. Once a friendly dog, Cujo is bitten by a rabid bat after sticking his head into a cave. Because he has not been vaccinated, the infection transforms him into a violent threat.
Donna Trenton and her young son Tad become trapped inside their Ford Pinto at the Camber property while Cujo attacks the vehicle. The story's tension comes from the heat, Donna's injuries, Tad's terror, and the family's isolation. King also weaves in references to Frank Dodd, the serial killer from The Dead Zone.
Cujo was published on September 8, 1981, and won the British Fantasy Award for Best Novel. King later said he barely remembered writing it because of his struggles with alcoholism during the period. The 1983 film adaptation changed the ending, making the novel's conclusion especially important to readers comparing the two versions.