For years, Ashby House has been on a top secret document listing Britain’s paranormal activity hotspots. But on this still and frosty January morning it stands quiet and innocuous, awaiting its new owner, world-famous photographer Lucille Shallot. Confined to a wheelchair after a bad accident, Lucille arrives in the company of her sister Laura, despite their deep and lifelong mutual loathing.

No sooner have the sisters made their entrance than Lucille suddenly vanishes into thin air. Laura, unaccountably distressed by the disappearance of her despised sister, sets about finding her, assisted by Steerpike the butler. But when they manage to penetrate the forbidden second floor, Ashby House comes to life and turns out to be quite a belligerent antagonist.