Eleven-year-old Jody Mitchell, Gabrielle Boni, is adopted by the loving couple Don Mitchell, William Katt, and Barbara Mitchell, Michele Greene. From the start, Jody’s bond with her father becomes intensely personal, and she grows increasingly jealous of anyone who spends time with him. This obsession twists into a troubling fixation, and she begins to see allies of her father as threats to their relationship. The tension in the new family dynamic quietly deepens as Don dotingly spoils Jody and Barbara works to hold the household together, even as she becomes the breadwinner because Don’s toy designs aren’t selling. What starts as a protective instinct soon darkens into something more unsettling, altering the family’s routine and trust.
Jody’s volatility erupts in violence when a school principal suggests she might need to be placed in a state-run boarding school, a move she perceives as a direct challenge to her father’s life. In a calculated act, Jody murders the principal, Mrs. Hemp, by luring her into a dangerous position and causing a fatal collapse of a shelf and books. She then violently files away the principal’s records, tearing the file to shreds in a park, erasing the trace of the crime in a single, chilling moment. The shock of this event ripples through the community and marks the first clear shift from misbehavior to outright psychopathy.
Jacqueline, the maternal grandmother, Jacqueline, Peggy McCay, becomes an early target in Jody’s bid to isolate Don. Jody taints Jacqueline’s trust with a plot that involves poisoned-looking juice and manipulation, attempting to coax Jacqueline into drinking while praising her father’s talent as a toy designer. When the plan backfires and Don nearly drinks the tainted liquid, Jody quickly steps in to prevent disaster. She later lures Jacqueline upstairs under the ruse of a game, and a brutal fall down the stairs follows. Jacqueline survives the fall but slips into a coma. Jody returns to the hospital later and sabotages Jacqueline’s ventilator, ensuring a grim outcome when the hospital staff struggle to keep her alive. The grandmother’s death serves as a stark demonstration of Jody’s increasing willingness to harm those closest to her.
The violence continues as Jody targets another family friend, Rachel Landers, Mimi Craven. After overhearing Rachel advising Barbara to consider divorce, Jody strikes with a brutal measure, beating Rachel to death with a fireplace poker. The body count climbs, and the circle around Jody tightens as the family contends with the visible consequences of her unchecked impulses.
Amid the mounting suspicion, Karen Conners, Roxana Zal, a college student staying with the family, starts to connect the dots. She looks beyond surface behavior and uncovers a troubling backstory: as a four-year-old, Jody witnessed the murder of her biological father by her biological mother, and she had already been moved from a previous foster home after the foster father was convicted of neglect following the death of his wife—an incident that hints at the darker pattern behind Jody’s actions. Karen’s discoveries prompt social services to become involved, increasing the pressure on Jody’s fragile façade.
The climax escalates as Jody pushes Barbara over the edge of a balcony when she fears the truth will come out, though Barbara survives the fall. The arrival of the social worker Mark Springer, Whip Hubley, triggers a final burst of violence: Jody bludgeons Springer to death with a heavy meat tenderizing mallet and then tries to shift the blame onto Karen. Don, who has been at a toy convention, returns to a scene of chaos: Barbara wounded, Springer dead, and Karen ready to testify. Barbara gathers the courage to reveal Jody’s crimes, and Karen calls 911. The truth leaves Jody crying and pleading for love and reassurance, but Don, now fully aware of his adopted daughter’s capabilities, rejects her with a cold finality. The family withdraws into comforting Barbara, leaving Jody to confront the consequences of her actions alone, as sirens wail in the background and the film leaves open the possibility of arrest or institutionalization for Jody.
