The film follows 17-year-old Cassandra Mortmain (Romola Garai), and the fortunes of her eccentric family, struggling to survive in genteel poverty in a decaying English castle. The characters include: Cassandra's father (Bill Nighy), a writer who hasn't written anything in the twelve years since the spectacular success of his first novel; Cassandra's exquisite older sister Rose (Rose Byrne) who rails against their fate and hopes to marry for money; and their bohemian stepmother, Topaz (Tara Fitzgerald), an ex-model still apt to sun-bathe in the nude. The possibility of salvation seems to loom in the form of their wealthy American landlord Simon Cotton (Henry Thomas) and his brother Neil (Marc Blucas). Although Simon initially turns her away, Rose is determined to make him fall in love with her and succeeds. A wedding is arranged and Cassandra appears left on the sidelines. But events spiral out of control, and before the summer ends many expectations will have been overturned.
What is the name of Cassandra's step mother?
Topaz