Donna Trenton finds herself trapped in her car with her son Tad by a rabid Saint Bernard who is intent on seeing them dead, while the summer sun slowly brings them to the brink of dehydration. Donna Trenton, wife to Vic and mother of four-year old Tad knows that having an affair will destroy her marriage and family, but she cannot let go of the need for more passion in her life. Being forced to move to Castle Rock. Maine, Donna has found her home life unbearable due to her husband's business slowly dismantling and putting them in a financial crisis that has led to a rift between Donna and Vic. Although she knows that isn't justification for her infidelity, Donna can't help but feel resentment towards Vic due to him uprooting their family from New York where they had been most successful. And the man she has taken as a lover, Steve Klemp, has given her the comfort she has needed in Vic's absence.
However, Donna realizes that she must end the affair once and for all and asks Steve over on a day she knows Vic is working late. When Steve arrives, he tries to engage Donna but she breaks it off with him, begging him to go for the sake of her family. This enrages Steve who storms off and vows to destroy Donna and her family.
Unknown to Donna, Vic knows about the affair which leads to increasing tension in the home. Due to his business, Ad Worx, being on the verge of collapse, Vic must make a business trip out of town in an effort to save his advertising agency and their way of life. The problem arising from a manufacturing malfunction that contaminated a batch of cereal which happens to be a product of one of their top clients. While he can't bring himself to resolve his issues with Donna, he does have the determination to save their marriage, but knows this this is not possible if the business implodes.
On the others side of town, the Camber family is dealing with troubles of their own. Joe and his wife Charity run a mechanic business and are well-known in the community, yet behind closed doors their marriage is anything but perfect. Charity must thwart of Joe's abusive personality and keep her son, Brett safe from his attacks on a daily basis. Charity secretly enters the lottery with the hopes of winning and being able to escape Joe. Much to her luck, she wins $5,000 and is able to convince Joe to let he go, though his only reason for doing so is he plans to leave for Boston and use the money to get away from his wretched life.
While the situation at home reaches a boiling point, the Camber's sweet St. Bernard, named Cujo finds himself bit by a rabid bat when he chases a rabbit into a nearby cave. The infection takes hold of Cujo transforming him from a sweet and loving teddy bear into a vicious monster.
The next day, Charity flees with her son Brett, refusing to spend another day in the house with Joe. Hours after she leaves, Joe meets with his neighbor Gary, a functioning alcoholic. The two of them shoot the breeze as Joe expresses his relief that Charity is gone and his plans for Boston. During their conversation, Cujo appears and Joe notices something isn't right. Cujo attacks Gary and despite his attempts to evade the dog, has his throat torn open and is killed. Cujo then turns on Joe who tries to get the police on the phone but is killed by Cujo before he can make a connection.
Meanwhile, Donna decides to take her Ford in for repairs at Joe's shop and drives with her son, Tad to the Camber's home. Unfortunately, the car finally bites the dust before she can drive it into the garage. Donna calls out for Joe several times, but no one appears. Realizing something is wrong, Donna begins to search the property but comes face to face with the rabid Cujo. He chases to her car and tries to break through the window but does not succeed. Thus, Cujo circles the car with Donna and Tad trapped inside.
As the hours pass, the heat from the sun makes the inside of the car unbearable, and without water Tad's health begins to fail. Donna tries to escape the car several times, but is thwarted by Cujo each time, eventually ending with her bitten several times and losing blood rapidly. As Tad begins to succumb to dehydration, Donna fears they are both doomed to die in the car.
Meanwhile, Vic returns home unexpectedly due to the fact he cannot reach Donna. When he arrives home he finds it broken into and completely in shambles. Vic calls the police who come to investigate the break in, he explains Donna and Tad are missing and that they possibly may have gone to the Cambers for home repairs. The Sherriff, George, volunteers to drive out to the homestead and see if his wife is there.
Sherriff George arrives at the Camber's home and spots Donna's car and radios to the station that he has located the vehicle. Donna tries to warn the Sherriff about Cujo but it is too late. The dog attacks him. The Sherriff attempts to shoot Cujo but his gun is snapped by his strong jaws, ending in a struggle that ultimately leads to the Sherriff's death.
Donna sinks into despair, realizing that if she isn't rescued soon that she and Tad will be dead before the day is over. Trying to keep Tad conscious, Donna devises a plan to escape when she spots a baseball bat in the lawn just a few feet away from the car. She knows she will only have one shot in reaching the bat while Cujo is distracted with the Sherriff's body and rushes from the car, grabbing the bat.
Cujo notices the movement and goes in for the attack, but Donna is able to hit Cujo several times with the bat, finally breaking it on his head. Cujo recoils from the blunt force and Donna uses that moment to stab him in the eye, driving the bat deep into his skull and killing him. Exhausted and overheated, Donna collapses as Vic arrives with several police cruisers. He rushes to Donna's side who begs him to get to Tad. Unfortunately, in the interim, Tad has succumbed to the heat died of heat stroke. Vic is completely distraught as an ambulance appears to take Donna to the hospital. The news of Tad's death crushes her and she has to be sedated.
Several months pass, and Donna and Victor are able to pick up the pieces and rebuild their life, though the absence of Tad is a pain they will live with every day. Charity and Brett return to Castle Rock to start a new life, free from the oppression of Joe whose death was a blessing in disguise. Charity is sad for Brett for losing his dog, and gives him a new puppy as a gift, a sign of a new future together.
Best part of story, including ending:
The characters in this story were all very unlikable. Everyone was so flawed that it was impossible to root for anybody except Cujo. I actually was happy as he killed everyone as no one felt like they were worth saving.
Best scene in story:
The scene with Donna Trenton taking on Cujo with the baseball bat is thrilling and visceral. I was on the edge of my seat the entire time and her determination to save her son redeemed her to a point.
Opinion about the main character:
Donna is just a horrible woman. While you understand her marriage is on the rocks, her blatant cheating makes her unlikable. While, her determination and love for her son redeems her to a point, most of the time you are rooting for the rabid dog.
The novel follows the troubled, and distressed lives of the people in Castle Rock, Maine. Destruction of the mind causes Donna Trenton to cheat on her husband, and Cujo to attack his loved ones. Fear is apparent throughout the whole book, when a rabid dog begins attacking people.
The review of this Book prepared by Dr. James Suddenburg