Sunflower is Sybil Fassendyll, a beautiful, 30-year-old actress at the peak of her career. For the past ten years, she has been the mistress of the brilliant but domineering Lord Essington. But when she meets American millionaire politician Francis Pitt in London, she soon leaves Essington and becomes involved with Pitt to the point of obsession. Though outwardly a powerful public woman, Sunflower secretly years for marriage and family, home and security.