Candy, Susan Sennett, is a 16-year-old girl who is kidnapped on her way home from her Catholic school. The three kidnappers include Eddy, his partner Jessie, and Jessie's brother Alan; they force her into their van, bind her, and bury her alive in a field in Southern California, hoping to secure a ransom from Candy's family. Unbeknownst to them, Sean Newton, Christopher Trueblood, an autistic boy living nearby, witnesses the crime. He goes home and tries to tell his intolerant parents—Dudley and Audrey Jerry Butts—what he saw.
The captors reach out to Candy's father Avery Phillips, Ben Piazza, demanding that he pay the ransom with the diamonds from his jewelry store. Avery stays silent and does not report the abduction to anyone, including Candy's mother Katherine Dolores Dorn.
The kidnappers dig Candy up and bring her to their hideout. Jessie and Alan plan to remove Candy's ear to present to Avery as leverage, but Eddy intervenes. The group then visits the morgue, bribing coroner Charlie Bill Woodard to remove an ear from a cadaver. Meanwhile, Eddy develops a protective bond with Candy, promising to safeguard her from further harm. After Jessie and Alan return, Eddy assaults Jessie, revealing darker, troubling traits.
Eddy presents the ear to Avery, who remains unmoved and reveals that Candy is his stepdaughter and that she stands to inherit $2 million from her late father when she turns 21; if she dies before then, he will receive half of the inheritance. Alan goes to the hideout with the intention of killing Candy. Sean infiltrates again and finds Candy, who urges him to contact the police. Alan returns and rapes her once more. Eddy interrupts and beats Alan. Sean escapes, but on his way home misinterprets Candy's instructions and uses a police doll to call a Jewish deli in Brooklyn.
Jessie and Alan persist in arguing that Candy must die. In the night, Eddy takes Candy to the grave, promising to return and rescue her. The next morning, he tells Alan that he killed her. As Sean watches them drive off, he tries to sneak back with a pair of scissors, but his mother stops him and gives him a downer to quiet him.
The group visits Katherine, who becomes intoxicated and is seduced by Alan. They have Katherine call Avery, who is having an affair with his employee Lisa Phyllis Major. Avery returns home to be held at gunpoint by the kidnappers as Alan murders Katherine. Avery then leads the captors to the jewelry store and delivers the contents of the safe, only to fail at retrieving his revolver. Alan attempts to shoot Eddy, who kills him. Eddy and Jessie try to escape, but Avery shoots Jessie and pursues Eddy to the grave site. A gunfight ends with Avery's death.
Eddy attempts to dig Candy up, but Sean shoots him dead with Avery's gun. Sean listens to Candy's breathing through the pipe. Audrey calls Sean with a cowbell, prompting him to make a trail to his house by sliding down the hill on his backside. Then a gunshot is heard, followed by the sound of the cowbell dropping and Candy's breathing in her underground prison. Her final fate remains unknown.
