Dan is a diabetic father hiding a secret from his family — he’s bisexual. He’s also in the middle of a trial separation he doesn’t want. His wife, Teresa, has been shutting him out, and his teen daughter, Charlie, and young son, Geo, are all he has left. At Charlie’s request, the family takes a trip together to a rental house on the coast, with Dan hoping the vacation will win them back. But the rental is owned by Reeny Baković, an intrusive host whose homophobia and meddling sour the trip. When Dan glimpses the apparition of Reeny’s late mother and discovers the old woman’s glasses hidden in a drawer, his unease hardens into dread. Her presence seems to watch him, and Dan becomes convinced she knows his secret
After a tense stay, he leaves a harsh review and the family moves onto a hotel — until he realizes he’s forgotten his insulin. Dan turns back to retrieve it, but on his return to the family, his blood sugar spikes catastrophically and he nearly dies — the fridge had frozen and destroyed his insulin. Teresa dismisses his fear that something sabotaged him, and even Dan doubts himself — until he unpacks at home and finds the dead woman’s glasses in his luggage. Seeking help, he turns to his friend Elara, who believes the revenant has attached to him and is feeding off his shame. To starve it, she says, Dan will have to face the very fears he’s spent his life hiding from. But he’s paralyzed by the risk of losing his family.
The Late Baković tightens her grip, able to affect the physical world, influence people, and manipulate technology. She costs Dan his job, deepens his rift with Teresa, and plants the truth in Charlie’s path — who keeps it to herself, her silence curdling into a resentment Dan can feel but doesn't understand. As he spirals, the spirit exposes him online to everyone he knows, driving him toward a breakdown and arranging circumstances so he'll kill himself. When he can't go through with it, she possesses him to finish the job, with Teresa and the children fighting to save him.
After surviving the ordeal, it's clear the only way to drain her power is for Dan to face himself. He finally tells his family the truth. Through Dan's painful honesty, Charlie's hard-won forgiveness, and the family's imperfect love, they rally around him as he destroys the glasses and banishes the Late Baković for good.