Dr John Falconer, recently appointed partner to old Cornwallis, is invited to a garden party at Pine Hurst, seat of the local lord of the manor. It is an occasion arranged to celebrate the twenty-first birthday of Simon Steel’s eldest daughter Beatrice, who introduces him to her three sisters, one of whom, seventeen-year-old Rosie, takes it upon herself to conduct him around the extensive grounds of the house. In a moment of indiscretion, she lets slip her true feelings about Beatrice who, she says, has always been over-possessive about Pine Hurst and, since the death of their mother, has become insufferably dominating. At that time, even though she was then only in her ’teens, Beatrice had taken over the running of the house and now she ruled her father and the servants with an iron hand. What was particularly frustrating for Rosie, who could see no end to the tyranny, was that no man had so far shown any willingness to marry Beatrice and thus deflect her from the object of her passion. As for Beatrice herself, her wanderings about the house and grounds convince her that no one could ever take the place of her most prized possession – although she constantly has to remind herself that it is her father who owns Pine Hurst. But she runs it and glories in being its mistress. Of course, he might decide to remarry – not that she would mind his taking another wife; it is the thought of another woman becoming mistress of the house that fills her with dread. But then, unexpectedly, her father dies, and when the family meet for the reading of the will, she realises her security is threatened and that she must begin to lay plans to protect her position and allow her the freedom to continue as before. The Obsession powerfully portrays a woman so driven by the need to protect her inheritance that she will sacrifice almost anything or anyone to ensure she does not lose it.