If you want to see explosive acting, just watch Judi Dench and Cate Blanchett ignite in this film version of Zoe Heller's 2003 novel. Director Richard Eyre (Iris) basically puts Patrick Marber's juicy script in front of these two queens and lets them dig in. Here's what you should know: Blanchett plays Sheba Hart, a new art teacher at London's St. George School. Beautiful and upper-class, Sheba has an older husband (the ever-amazing Bill Nighy) and a son with Down syndrome. She is also having it on with Steven Connolly (Andrew Simpson), one of her fifteen-year-old students. It's Sheba's bad luck that while giving Steven a vigorous blow job she's caught by Barbara Covett (Dench), a lesbian teacher who agrees not to make a scandal if Sheba will become her friend. There's more, much more. And until the film goes off the deep end of melodrama, you'll be riveted. This is the bravest, riskiest role of Dench's brilliant screen career. Barbara narrates the film, unreliably, in a voice that is sympathetic mostly to herself. Dame Judi lets us know this is a woman of dark secrets. It's spellbinding to watch her blow the lid off.