Joyce Smith, Lin Shaye, is an elderly housewife who is left distraught when her husband Fred dies in a slip‑and‑fall accident while repairing the roof. A probate attorney explains that Fred owed a substantial loan, and Joyce has only about $2,200 in savings with no other assets in his name.
In the library, Joyce spots a magazine about turning properties into a bed and breakfast, and she eventually converts her house into one. A young writer, Valeska Miller as Sarah, and her husband Casey Nicholas Price as Edward become the first lodgers. Joyce forms a bond with Sarah, but Edward is put off by her demeanor; the couple leaves, though they stay in touch through letters.
Soon after, a handsome young man named Robert moves into Joyce's house, Oliver Rayon. She becomes infatuated with him, preparing special dinners, dressing up, and even getting a satellite dish so he can watch an all‑football channel. After divorcing Edward, Sarah visits Joyce and shares an intimate night with Robert, which creates a rift between Joyce and Sarah.
Joyce’s neighbor Gladys tells Sarah that she once fell out with Joyce due to Joyce’s split‑thinking and abandonment issues. Gladys also reveals that Fred forced Joyce to abort a baby. After Sarah leaves, Joyce goes to Gladys and suffocates her with a pillow. When Robert asks where Sarah went, Joyce lies and says she has returned home to her husband, making Robert feel worthless. He later catches Joyce going through his belongings and confronts her; she tells him he reminds her of her son who died years ago. Robert accepts the lie but remains cautious.
Joyce prepares a home‑cooked meal for Robert, but spikes his food and then rapes him while he is unconscious. She later finds money and cocaine in his belongings, suggesting he is involved in drug trafficking. After awakening, Robert finds a letter from Sarah revealing Joyce’s lies and manipulations. He confronts Joyce and collects his belongings, intending to move out, but Joyce bludgeons him with a frying pan, killing him. She reads the rest of Sarah’s letter to Robert, in which Sarah reveals that she is pregnant.
Joyce, who has always wanted a child, invites Sarah to stay at her home while Joyce takes a vacation using Robert’s drug money. Joyce then buries Robert’s remains in the backyard and gets rid of his personal items. Sarah goes to Robert’s old room but finds it locked. Unbeknownst to Sarah, Joyce has redesigned the room into a nursery, leaving behind a welcoming sign from grandma, foretelling her return after Sarah has given birth.
