Richard Marquand directed this second-rate retread of Haunted House Horror, with The Devil added to spice up the proceedings. Katharine Ross and Sam Elliot play Margaret Walsh and Pete Danner, a couple of American architects who are inexplicably summoned to the English countryside for an architectural assignment. They meet a mysterious and reclusive millionaire, Jason Mountolive (John Standing), get one look at him, and head back to town. But when they are forced off the road by a chauffeur-driven limousine, they find themselves back at Mountolive's house of horrors. Trapped in the mansion for the weekend, they get to see Mountolive's guests dispatched in a variety of gruesome ways, before the inevitable demonic possession routine kicks in.
by Paul Brenner synopsis