In 1900, young Reverend Henry Bull and his sister, Kitty, are tasked with taking over the duties of their family home in Essex, a majestic Victorian mansion built on the site of an old monastery. Unaware of the sinister forces that lurk within, the pair are soon confronted by terrifying paranormal activities that threaten their loved ones. Desperate to protect themselves from the demonic intrusion, they call upon the services of a trusted family friend to investigate the origins of the vengeful ghosts which haunt their property. But these are spirits who will not rest, and Borley Rectory is doomed to gain a chilling reputation, as the most haunted house in all of Britain.