While filming a haunted asylum in St. Louis, Missouri, documentary filmmakers uncover a secret diary of the infamous 1949 exorcism involving a 13 year old boy possessed by the devil that later inspired the book and movie, The Exorcist. Utilizing hi-tech paranormal gadgetry along with a legion of supernatural experts they search out to capture the scariest entity known to man, The Unholy Ghost. Nothing you have ever seen or heard before gets you closer to the ungodly truth of what really happened in this most terrifying, best selling story of all time! This is the untold-real story of The Exorcist, a chronicle of true events based on the actual priest's secret diary the world was not to see, Until Now!