If you don't already worship at the Church of Judi Dench, Notes on a Scandal may be the film that causes your conversion. Dame Judi tears into the meaty role of secretive spinster teacher Barbara Covett with relish. You won't soon forget the look on her shriveled face as she commits outrageous acts of emotional blackmail.

Narrated by Barbara from her own diary entries, what we have here is a classic case of a very unreliable narrator, but one with a quick wit. As the new term begins at a bustling lower-class middle school, history teacher Barbara, who is utterly burned out and simply going through the motions (she calls education 'crowd control'), is beguiled by the new art teacher Sheba Hart (Cate Blanchett), a 37-year-old upper-class beauty who really believes in teaching.

Overwhelmed by the throngs of rowdy kids, Sheba needs help, and Barbara steps right in, aggressively pushing her friendship onto the grateful Sheba and insinuating herself into Sheba's family, to the annoyance of Sheba's much older husband Richard (Bill Nighy).

Things begin to spin wildly out of control when Barbara encounters Sheba having sex with one of her art students, the pouty 15-year-old Steven (Andrew Simpson), a 'tower of testosterone' (as Barbara puts it) with a lilting Irish accent. Frenzied with rage and jealousy, Barbara quickly realizes that she can extort permanent friendship from Sheba. They share a secret that could destroy Sheba's life. It's a brilliant power play, and the grateful Sheba succumbs without a fight.

Sheba vows to break up with Steven, but his hard-luck stories (and that cute accent) keep her coming back for more. As it turns out, he's enjoying his own little power play. When Barbara realizes that her 'best friend' has betrayed her again, the situation devolves into near chaos, leading to several wild scenes of outrage, histrionics, recriminations, and revelations of disturbing secrets.

This is fun stuff, and Dench revels in it. Shot in extreme close-up and looking every one of her 72 years (and then some), Dench is utterly without vanity and a complete horror. In the course of the film Barbara is called, among other things, a 'crone' and a 'vampire,' both apt descriptions. She is a joy to watch. It's easy to see the madness hiding right behind her squinty eyes.

Blanchett is a perfect foil. In a film that's ultimately about the amazingly toxic effect of chronic loneliness, she makes it easy to see how even a busy wife and mother of two can feel alone, trapped in a soul-crushing marriage and looking for any kind of stimulation. Some of the most emotional climactic scenes, shot within the confines of Barbara's claustrophobic basement apartment and propelled by one of those urgent and nervewracking Philip Glass soundtracks, give us the pleasure of watching two real masters at work.

Here's hoping Dame Judi gets many more chances to strut her stuff. Do 007 for your bank book, Judi, but do these films for us.

The DVD includes a commentary track from Eyre, two making-of featurettes, an interview with Blanchett, and promotional webisodes for the film.

Scandalous, darlings.