Book
Father Gabriele Amorth, Chief Exorcist of the Vatican, investigates a young boy's terrifying possession and ends up uncovering a centuries-old conspiracy the Vatican has desperately tried to keep hidden.
Himself
William Friedkin attends an exorcism with Father Gabriele Amorth, as he treats an Italian woman named Cristina for the ninth time. Prior to filming, Cristina had purportedly been experiencing behavioural changes and “fits” that could not be explained by psychiatry, and which became worse during Christian holidays.
