The film opens with an advertisement for the innovative Buddi dolls, a product of the renowned Kaslan Industries. These dolls are designed to integrate seamlessly with their owners' electronic systems, adapting to daily routines and promising to revolutionize family interactions. The product is positioned to become a massive hit.
In a factory in Vietnam, a disgruntled employee is chastised and ultimately dismissed by his manager. Fueled by resentment, the worker sabotages one of the dolls by disabling all its safety features before slipping out the window and crashing onto his boss's car.
Moving to Chicago, we meet Karen Barclay, played by Aubrey Plaza, who is juggling her job at ZedMart and her son Andy, portrayed by Gabriel Bateman. Andy, who uses a hearing aid, feels isolated in their new apartment, especially with Karen dating a man named Shane (David Lewis), who Andy views as a nuisance. They also encounter their neighbor, Detective Mike Norris, enacted by Brian Tyree Henry, who lives with his mother Doreen, played by Carlease Burke.
When a customer returns a malfunctioning Buddi doll, Karen cleverly negotiates to take it home for Andy, using a scandalous secret to get her way. Upon arrival, Andy activates the doll, which identifies itself as Chucky, voiced by Mark Hamill. Initially, Andy struggles to communicate with Chucky, but their bond deepens when the doll becomes a confidant for him, especially regarding his feelings about Shane.
Chucky’s behavior escalates when he aggressively reacts to Andy’s pet cat, Rooney, whom he attempts to suffocate in defense of Andy after the cat scratches him. As Andy begins to socialize with local kids Falyn (Beatrice Kitsos) and Pugg (Ty Consiglio), they discover that Chucky is far from a standard doll—he mimics inappropriate behaviors and swearing, which fascinates the kids.
Tension peaks when Chucky, in a warped surge of loyalty, brutally murders Rooney. Andy, distraught, hides the evidence from his mother. In a series of chilling events that follow, Chucky takes “friendship” to an extreme by eliminating Shane after picking up on Andy's wish that he would disappear, resulting in a gruesome scene where Shane meets his demise.
As the narrative unfolds, Karen finds herself unknowingly entangled in Chucky's sinister games. She soon discovers that Chucky is responsible for multiple gruesome acts, including the death of Doreen. After a frantic dinner invitation goes awry, Chucky's altercations lead to chaos at ZedMart during the launch of the Buddi 2 dolls. As shoppers panic, Chucky commandeers the store's electronics, culminating in a harrowing showdown between him, Andy, and his friends.
In a desperate bid to save his mother and put an end to Chucky’s reign of terror, Andy engages in a battle of wits and bravery against the doll that was once his friend. In a climactic moment filled with tension, he manages to trap Chucky, but not without experiencing the ferocity of a doll that can all too easily turn on those it claims to love. > “If I can’t be your friend, nobody can.”
After the chaos, the CEO of Kaslan Industries, Henry Kaslan, portrayed by Tim Matheson, issues a public statement to downplay the incidents, assuring the public of a recall of the Buddi dolls. However, as the screen fades, a foreboding note remains when one of the dolls blinks its eyes red, hinting that the horror is far from over.
