NYPD homicide detective Julie Miller made her name by catching Father Sunday, a notorious satanic serial killer, and saw him executed for his crimes. Thirteen years later, Julie is a single mother raising her 12-year-old son, Max, when a fresh series of ritualistic killings begins in New York – murders that appear to be connected to her past. As her investigation draws her deeper into a world of demonic possession, a malevolent force turns its attention to Max, and Julie must turn to priests, among them a former convict who has found his vocation, to protect him. Set within the world of The Exorcist but neither a remake nor a reboot, the film combines a dark serial-killer investigation with supernatural horror.

The seventh film in the series that began with William Friedkin's The Exorcist (1973), following The Exorcist: Believer (2023). Mike Flanagan wrote, directed and edited the film, taking some inspiration from The Exorcist III, which also mixed a murder investigation with demonic possession. Scarlett Johansson leads a cast that includes Chiwetel Ejiofor, Laurence Fishburne, Diane Lane and John Leguizamo, alongside many regulars from Flanagan's earlier films, such as Kate Siegel, Rahul Kohli, Samantha Sloyan and Carla Gugino.