A young seminary student in a crisis of faith (Colin O’Donoghue) goes to Rome for special training in exorcism, where he meets a veteran exorcist (Anthony Hopkins) and finds his faith tested further and finally reaffirmed. “Inspired by true events” say the credits, and we know what that’s worth—one event, no doubt, was the release of The Exorcist in 1973 (Michael Petroni’s script was reportedly “suggested” by Matt Baglio’s nonfiction). For all its formulaic familiarity, the movie is surprisingly effective. Petroni and director Mikael Håfström eschew sensational shocks in favor of an atmosphere of mystery, dread and—given the subject matter—relative understatement; it’s what The Exorcist might have been if it hadn’t been made by heavy-handed hacks. Alice Braga and Ciarán Hinds give dignified support.