In Spring 1976 in Tarkers Mills, on the night of a full moon, the town drunk, Arnie Westrum, is attacked and decapitated by a werewolf. However, the county coroner claims his death resulted after he fell asleep on the railroad tracks. Teenager Jane Coslaw is annoyed by the antics of her younger brother, Marty, and his prankster friend, Brady Kincaid. After they frighten her with a snake, Jane falls into a mud puddle and refuses to speak to her wheelchair-bound brother. Jane later softens when Marty apologizes and gives her money to replace her torn panty hose. Sometime later, a woman named Stella Randolph is attacked and brutally killed by a werewolf, after it breaks through her bedroom window. Following the murder, Marty escorts classmate Tammy Sturmfuller home on their last day of school before summer break. He rides alongside her in “the Silver Bullet,” the gas-powered wheelchair made by his beloved “Uncle Red.” Tammy tells Marty that she is frightened after hearing strange noises coming from the greenhouse on her property. Marty wants to investigate, but is concerned the Silver Bullet will get stuck in the mud. Following his third divorce, Uncle Red comes to visit. Marty’s mother, Nan Coslaw, is not amused by her heavy-drinking brother, and asks Red not to drink around Marty. In time, Tammy’s father, Milt Sturmfuller, hears noises coming from the greenhouse, and takes his rifle to investigate. He is killed after a wolf breaks through the floorboards and attacks. The townsfolk are on high alert, fearing the unidentified “maniac” behind the killings. At a local pub, Andy Fairton criticizes Sheriff Joe Haller for not catching the killer. Herb Kincaid comes into the bar and announces that his son, Brady, is missing. The sheriff finds Brady’s mutilated body in the park. Marty and his family attend the funeral, and Reverend Lowe offers words of comfort. Marty suggests to Uncle Red that the killer might be a werewolf, and his uncle laughs at the notion. Andy Fairton organizes a manhunt, but Sheriff Haller calls the search a “lynch mob” and orders they disband. Grief-stricken Herb Kincaid chastises the sheriff, and the search party sets off into the night. Reverend Lowe pleads with the mob to call off its search, but his request is ignored. Several townsfolk are killed when they are attacked in the foggy woods. Reverend Lowe has a nightmare of the townspeople turning into werewolves, and wakes up screaming. Tarkers Mills cancels the town carnival and enforces a curfew. Uncle Red surprises Marty with a new Silver Bullet he built, which resembles a motorcycle. Marty speeds down the street, passing cars along the way, and “popping wheelies.” Uncle Red bids farewell, and leaves Marty with a bag full of fireworks. Sometime later, Marty sneaks out of his house to set off the fireworks in the woods, and attracts the attention of the werewolf. As the creature approaches, Marty fires a rocket at it, striking its eye, then escapes on his Silver Bullet. He telephones Uncle Red the next morning and tells him he saw a werewolf, but his uncle does not believe him. Marty then tells his sister, Jane, what he saw. Under the ruse of a charity “can drive,” Jane knocks on doors, secretly looking for a resident with an eye injury. She begins to doubt Marty, and delivers her collected bottles to the church when she discovers that Reverend Lowe has a bandaged eye. He follows her into a shed, and she flees terrified. Jane asks Marty what they should do, as she fears adults will not believe them. Marty writes several anonymous letters to the Reverend, claiming to know his secret, and urging that he end his own life. Uncle Red visits a few days later, refuses to believe Marty, and is alarmed to hear of the sibling’s antics. Sometime later, Reverend Lowe follows Marty in his automobile, and tries to run the boy off the road and over a bridge. Marty narrowly escapes, and drives the Silver Bullet onto a deserted covered bridge, where it runs out of gas. Reverend Lowe’s automobile gets stuck in the mud, but he pursues Marty on foot, apologizing for what he is about to do. Marty pleads for his life, as Lowe threatens to drown him in the river. Marty is saved when he shouts to a passing farmer, and Reverend Lowe flees. When Marty returns home, Uncle Red refuses to believe him, until he finds Lowe’s automobile paint on the Silver Bullet’s fender. He reports his findings to Sheriff Haller, and urges him to investigate. The sheriff goes to the church at night, in search of Reverend Lowe, and sees the paint scrapes on the preacher’s automobile. Sheriff Haller attempts to arrest Lowe, who turns into a werewolf before his eyes. The werewolf kills the sheriff with a baseball bat to the head. After the sheriff disappears, Marty and Jane ask Uncle Red to turn their silver medallions into a bullet, and he reluctantly agrees. On Halloween, the night of the next full moon, Uncle Red and the siblings await the werewolf’s attack. The creature cuts off the power to their house, and breaks through the living room wall. In the chaos, Uncle Red drops the silver bullet and it falls down a vent. The wolf throws Uncle Red across the room, and goes after Jane, as Marty tries to retrieve the bullet. Uncle Red pulls the wolf off of Jane, as Marty reaches the silver bullet and loads the gun. He fires a shot into the creature’s good eye. The werewolf collapses and transforms back into Reverend Lowe, making a final lurch before dying. Marty lightens the moment with a joke, and embraces Jane.