Protecting a death-threatened actress, private detective Cordelia Gray finds that her own life is in grave danger. Beautiful but neurotic actress Clarissa Lisle is hoping to make a spectacular comeback in Webster's The Duchess of Malfi, to be played in Ambrose Gorringe's sinister castle on Courcy Island. But Clarissa has been receiving poison-pen letters threatening her life, and her husband, Sir George, has hired Cordelia to ensure his wife's safety. Clarissa prepares for her leading role as the ill-starred Duchess, but before the curtain rises in the castle theatre she has already acted out her death scene. And everyone confined within the walls of the Gothic castle seems to have an excellent motive for sending her 'down, down to hell'.