Corey Bachman is the only son and child of Jeffrey and Mildred Bachman. They live together in the quiet enclave of Bridgewater, Jupiter.
Twisty the Clown breaks into the Bachman home during the night, intending to kill Corey's parents so that Corey would not have to do anymore chores. Jeffrey Bachman wakes and gets up, leaving Mildred sound asleep. He leaves their bedroom, and Twisty silently stalks him down the hall and kills him without rousing Mildred and Corey.
Corey's mother, Mildred, stirs in her sleep and wakes to see Twisty standing right beside the bed. She screams at the sight of him and he leans over and violently stabs her repeatedly.
Twisty then walks back into the hall and pushes into Corey's room. Twisty leans down and hoists the screaming boy over his shoulder, taking him to his campground and caravan in the woods. After Corey is abducted from his home, he is kept in a cage inside the caravan with the previously captured Bonnie Lipton.
A week later, a breaking news announcement interrupts the radio's scheduled program and a reporter announces two additional fatalities. Neighbors entered the Bachman home, found the bodies of Corey's parents and reported the murders to Jupiter Police. The reporter tells the public that their autopsies confirmed the victims had been dead for 'at least a week'.
Meanwhile, Corey sits huddled in a corner of the cage and hugs his knees to his chest. Bonnie tries to persuade him to eat and squeezes some bread through their cage divider. Corey accepts a single piece without a word and then huddles back into a ball. Bonnie attempts to comfort the boy, assuring him that they will be found eventually and that his parents will never stop searching for him. Corey looks deadpan and says "I think he killed my parents".
While trapped in the caravan, Corey is terrorized by Twisty's failed entertainments and becomes malnourished from a lack of food. On Halloween night, a costumed and masked Dandy sneaks into the caravan when Twisty is away. He finds Corey and Bonnie alone, and offers them some packaged candy. Corey reaches through the cage and takes a piece. Dandy then turns to Bonnie and offers the candy, but she is wary and doesn't move any closer. Corey flinches and scrambles backward as Dandy begins to stab a knife and stick through the cage.
Twisty returns with Mike, his latest victim. Corey has fainted from hunger. Mike wakes up inside the cage, and asks Bonnie if Corey is dead. Bonnie clarifies that he is just malnourished and weak. She instructs Mike to untie her feet before Twisty returns. When he opens the cage, Bonnie waits for Twisty to turn his back and then pushes him over, fleeing and leaving Corey and Mike trapped. Bonnie makes it to the road and manages to attract the attention of Jimmy and Maggie as Twisty tackles her from behind and carries her back to Corey and the cage. Jimmy and Maggie discretely follow Twisty back to the caravan, where they too are captured with the assistance of Dandy. Corey is forced to sit on the ground outside and watch Dandy's saw act. Jimmy awakens and screams at them all to run. Corey flees through the trees with Bonnie, Mike, and Maggie. With Dandy close on their tail, Maggie tells Corey and the other captives to run for the road while she sacrifices herself as a distraction. Corey and his fellow captives all escape and are found by bystanders. They call the police and their ordeal comes to an end.