On holiday in Ireland, two men discover a manuscript in the ruins of an old house, on the edge of a great pit. The manuscript describes the story of the recluse who was the last occupant of the house, believed by the locals to have been built by the devil, and the strange and terrifying experiences that befall him. After defending the house against an attack by evil swine-like creatures that appear from the pit below the house, he is transported through time and space to witness the end of the solar system, before returning to the house to face the final horror.