In this documentary, William Friedkin turns his lens on the world of exorcism, focusing on the renowned Catholic priest Gabriele Amorth. Friedkin, the Oscar-winning director of The Exorcist, explores the enduring fascination with demonic possession and the Church's ritual of exorcism through the experiences of Father Amorth, who claimed to have performed tens of thousands of such rites. The film serves as a companion piece to Friedkin's classic horror film, examining the real-life beliefs and practices that inspired it. By documenting Amorth's perspective and work, the documentary delves into the intersection of faith, fear, and the supernatural, offering a stark contrast to the fictionalized terror of its cinematic predecessor.