Liza and her son Jude endure a harrowing home invasion carried out by two masked intruders, leading to lasting psychological scars. While Liza struggles with haunting nightmares, Jude becomes mute, relying on a notepad to communicate. In an effort to heal, Liza's husband, Sean, proposes they move to the countryside. They settle into a manor house, unaware of its sinister past.
Upon their arrival, the family begins to explore their new surroundings. During this adventure, Jude uncovers a porcelain doll buried in the dirt, while Liza and Sean investigate a dilapidated mansion on the property. When Liza realizes Jude has gone missing, panic ensues, and she finds him clutching the doll. Feeling a strange connection, Liza decides to clean the doll, naming it "Brahms," bringing new life to the old toy.
The following day, at Jude's insistence, Liza and Sean take a stroll through their expansive grounds. Here, they encounter Joseph, the caretaker, along with his loyal dog. Tension escalates when Sean presses Liza to discuss their traumatic experience during the burglary, but she remains distant.
Later, unusual occurrences unravel within the house. To their astonishment, Liza and Sean overhear Jude speaking in his room. When questioned, Jude confirms he’s speaking to Brahms. The family’s therapist becomes involved as they share concerns about Jude's increasingly erratic behavior.
Joseph confides in Jude about his missing dog, yet no one seems to recall seeing it. Liza stumbles upon unsettling drawings, which she fears are manifestations of Jude’s trauma. During a tense dinner, Jude notes that Brahms' plate is absent, prompting an argument with Sean over the relevance of the doll. When things escalate, Jude leaves for the mansion with Brahms, leaving behind a chilling note: "I told you not to make him mad."
Joseph soon appears and, while recounting the tragic story of the house’s previous residents, reveals that a boy named Brahms once lived there and was responsible for two murders, remaining inside the mansion for three decades. Just as Sean's brother visits with his family, an accident injures Will, Jude's cousin, further amplifying Liza's distress.
Joseph's dark side emerges when he strikes Liza, leading her to demand to know Jude's whereabouts. He ominously tells her that "Brahms and Jude are gonna be one." In a desperate bid for freedom, Liza manages to escape in search of her son.
Sean ultimately discovers Liza and Jude in the basement, where he violently attacks Brahms with a croquet stick, unearthing a grotesque sight beneath the doll's facade. Terrified, Joseph forewarns that "It will never be over," revealing the depths of Brahms' malice before a furnace explosion kills him, sparing Liza, Sean, and Jude from harm.
Eventually, the family returns to their city life, momentarily feeling safe. However, as Jude prepares for bed, a chilling reveal occurs; he dons a porcelain mask, whispering goodnight to Brahms and ominously stating that everything will be alright as long as his family adheres to the rules.
