Soon after architect Mark Lamphere (Michael Redgrave, Dead of Night) marries Celia (Joan Bennett, Suspiria), she gradually begins to suspect that he has a past life that he s been keeping from her. But she doesn t know the half of it, and when he leaves on a business trip, she starts to uncover the sinister secret of his purpose-designed house and its apparent surplus of rooms, the seventh of which is kept firmly locked. What lies beyond its door?