When Annie Graham's secretive and estranged mother Ellen dies, the Graham family — Annie, her husband Steve, teenage son Peter, and strange young daughter Charlie — begins to unravel emotionally and psychologically. Annie, a miniature artist who recreates scenes from her own life, begins attending a grief support group where she meets a woman named Joan, who introduces her to séance-like rituals promising contact with the dead. A devastating tragedy midway through the film tears the family apart further and sets in motion a series of increasingly horrifying supernatural events centered on Charlie's memory. As Annie digs deeper into her mother's hidden life and occult connections, it becomes clear that the Graham family has been the target of a generations-long conspiracy tied to a demonic cult devoted to the demon Paimon. The film culminates in a shocking, nightmarish revelation that recontextualizes everything that came before, leaving virtually no survivor unscathed.