 In 1938, in London, the successful and famous theater actress Julia Lambert (Annette Benning) has an open marriage with her husband and manager, Michael Gosselyn (Jeremy Irons). She meets Tom Fennel (Shaun Evans), an ambitious young man of half of her age that wants to socially rise, they have an affair and she has a crush on him. Later, Tom has an affair with the aspirant starlet Avice Crichton (Lucy Punch) and uses Julia to get a part for Avice in her new play. Julia travels abroad, visits her mother and when she returns to London, she plots a magnificent revenge.