The Case of the Residential Evil

The owner of a large, beautiful country house is being mentally tortured by disembodied, demonic voices that seem to know his every move, his every thought. Are these spirits previous occupants that have been hidden in the house for centuries recently awoken or something altogether more hellish? At his wits end and after weeks of this constant harassment the owner calls in the Demonologist for help. When the Demonologist arrives he discovers that not only does the house have some terrifying secrets, so does the owner. The Demonologist takes on this challenging case where this supernatural foe has no physical form at all. How do you battle something that you cannot see but only hear?