Compelling look at obsession based on Zoe Heller's 2003 novel. Attractive Sheba Hart (Blanchett) is a novice art teacher who's given guidance by acerbic veteran Barbara Covett (Dench). Sheba has a much older husband (Nighy), two children, and a vague dissatisfaction with her comfortable life, which soon leads her into a relationship with her very willing 15-year-old pupil Steven (Simpson). When the bitter, lonely Barbara discovers Sheba's indiscretion, she ruthlessly uses emotional blackmail to tether the younger woman to her. But as Barbara's neediness grows, even the self-destructive Sheba finally has enough until the inevitable showdown. Disturbing and dazzling, thanks to the no-holds-barred performances of both Dench and Blanchett.