Abby Lia McHugh and her sister Kellie Kerris Dorsey are coping with the death of their mother Lexy. Kellie discovers a necklace that once belonged to Lexy and realizes it can move objects around, and she begins to wonder if the pendant could be connected to a restless, lingering presence from her mother's past. The mysterious totem soon makes its presence known by knocking over a jumble of trophies in Kellie’s room, a sight that makes their father James James Tupper worry that Kellie is attempting to sabotage his relationship with his girlfriend Robin Ahna O'Reilly, who has just moved in to help run the house.
Robin tries to take on household duties to help Kellie feel like a normal 17-year-old, but the disruption unsettles Kellie even as she tries to be kind toward her new family. Late one afternoon at track practice, Kellie is startled by the vision of a standing corpse wrapped in plastic on the bleachers, a moment that heightens the sense of something unseen watching them. Back at home, Robin is seen dealing with trauma in unsettling ways, gagging on long strands of blond hair and appearing deeply shaken by the strange events around them. Bernard, Lexy’s father, visits and meets Robin, and in conversation it’s revealed that Robin knew Lexy and James and had been a mutual friend in the past.
Kellie sets up Christmas ornaments on every door and installs motion detectors to gather evidence of the entity, hoping to convince the family something otherworldly is at work. When nothing moves at first, she notices the entity is more reactive around the family cat; whenever the cat is present, the motion detectors beep frantically and the cat darts away. Kellie grows more desperate and even threatens to burn the totem, and the entity retaliates by making a bookcase fall, crushing the cat in a sudden, devastating moment.
That night, the entity strengthens and attempts to abduct Abby. The family calls Bernard for help; at first he refuses to believe them, but after hearing more about the possibility that the entity might be his late daughter, he rushes back into the house, putting everyone in greater danger. Kellie’s boyfriend Todd [Braeden Lemasters] arrives with some obscure information on how to destroy totems, offering a glimmer of hope even as the danger escalates. Kellie hides Todd in her room and redirects her anger toward Robin, telling her that the mess is her fault.
Bernard is struggling with respiratory issues, and Kellie, in a misguided bid to help, uses up all the inhaler puffs, leaving him unable to breathe and, tragically, dying as a result. Robin, while searching for Abby, discovers a wedding ring hidden at the base of one of Kellie’s trophies. When Robin confronts Kellie, Kellie asserts that her mother was weak and that her father needed someone stronger, before pushing Robin into a bathtub; Robin strikes her head and appears to drown.
Kellie then strikes Todd from behind, killing him instantly, and she hurries to pull Abby out of the crawlspace where she had been hiding. James arrives and confronts Kellie with the terrible truth: the bodies in the house are the result of Kellie’s actions. Kellie knocks him unconscious and ties him to a chair while she struggles to destroy the totem. James briefly regains consciousness and pleads with Kellie to stop, but she remains determined to force a dangerous, twisted bond between them that she believes they share. Robin wakes up and emerges to try to save James and Abby, while Kellie pursues Robin with a glass shard.
The moment of reckoning comes when Kellie’s mother’s spirit appears, scaring Kellie and causing her to stumble. A violent end follows as Kellie is impaled on a jagged piece of sculpture, ending the immediate danger but leaving the three of them in a fragile, unsettled state. The film closes with the three of them huddled inside a tiny, parked house in a quiet, deserted location. They seem to be starting to heal, though Abby continues to talk to someone, hinting that the past may still be listening.
