The Rolfes -- Ben, wife Marian, son David, and Aunt Elizabeth -- are a pleasant family from New York seeking to escape from the doldrums of a summer in their Queens apartment. They find a beautiful old country mansion on Long Island -- restful, secluded, with pool and private beach -- perfect, for the right people. But their "Perfect" summer home hides terrors beyond their wildest imaginings. During that long summer the house becomes a nightmare from which there seems to be no escape.