'She had saved her. But at what a cost! Her position, her name, her character - she had given them all, but Clarissa was hers.' Upon the death of her mother, Agatha Bodenham finds herself alone for the first time in her life. Solitary and socially awkward by nature, she starts to dream about her imaginary childhood friend - the only friend she ever had. Much to her surprise, Clarissa starts to appear, fleetingly at first, and engage with her, and eventually becomes visible to everyone else. Agatha, a 32-year- old spinster, must explain the child's 'sudden' appearance. In a moment of panic, she pretends that Clarissa is her own daughter, her love child. Olivier constructs a mother/daughter relationship which is both poignant and playful. As the years roll by and Clarissa grows into a beautiful young woman, Agatha's love becomes increasingly obsessive as she senses Clarissa slipping away, attracted by new interests and people her own age.