In the tradition of 1987's "Fatal Attraction," 1992's "Single White Female," 2001's "The Glass House," 2002's "Swimfan" and 2003's "Cold Creek Manor," "Notes on a Scandal" is the latest edition of the "...from Hell" thrillers that have been a staple of the genre for just about as far back as talkies have existed. With acting royalty like Judi Dench and Cate Blanchett headlining the cast and British accents running rampant, of course the picture is dressed up to appear of a higher class than that. For all intents and purposes, though, it remains a consistently watchable, exceedingly overwrought potboiler that doesn't jump the rails until the disappointingly trite final scene. Until then, outstanding performances and some sharply provocative writing save the day.

Barbara Covett (Judi Dench) lives for her diary, going out into the world and cooking up experiences and internal fantasies that she then juicily gossips about for her own entertainment. Approaching the age of retirement as a high school professor, Barbara has become disenfranchised with today's youth and cynical of the future. Her lonesome existence is given newfound life when she meets new teacher Sheba Hart (Cate Blanchett), a wet-behind-the-ears type whose idealistic hopes far exceed her humble capabilities. They become close friends, with Sheba going so far as to invite Barbara into her home to spend time with her family—much-older husband Richard (Bill Nighy), teenage daughter Polly (Juno Temple) and Down Syndrome-afflicted son Ben (Max Lewis). The power in their relationship quickly shifts to Barbara when she witnesses Sheba having a sexual encounter with 15-year-old student Steven (talented newcomer Andrew Simpson). Desperate to keep her illegal affair secret, Sheba promises that she will end things with Steven—a declaration easier said than done. In turn, Barbara uses what she knows as a passive-aggressive blackmailing scheme that Sheba has no way of escaping.

Whether it be referred to as a " co-worker from Hell," "friend from Hell," or even "pent-up lesbian from Hell" picture, "Notes on a Scandal" has been directed by Richard Eyre (2004's "Stage Beauty") with a penchant for fascinating character psychology. Told from the point-of-view of the antagonist, the film invites the viewer into Barbara's head from minute one. Her mind is overloaded with catty, pretentious, unforgiving thoughts, but in Sheba she meets someone who is kind enough to like and weak enough to manipulate. Hints are made about just how possessive Barbara can get—another gal from her past who is now out of her life was apparently Barbara's previous target for infatuation—and beneath a calm, cool exterior lives a sad, destitute, and possibly mentally disturbed older woman. Audience sympathies are with Sheba throughout, even when she commits some wrongdoings, but Barbara is three-dimensionalized enough that she can't just be labeled a "bad" person.

Judi Dench (2006's "Casino Royale") and Cate Blanchett (2006's "The Good German") savor portraying such flawed, multilayered people. Dench is a tour de force in one of 2006's most rattlingly effective and complex performances. Her Barbara has long ago embraced a strict, authoritarian approach to teaching and existing as a way of getting respect, but in doing so has alienated those around her and cut off all chances for meaningful relationships. At the onset, Sheba clings to Barbara just as everyone else pulls away, seeing in this experienced elder woman someone to be respected and looked up to. Only after she gives in to her desires for the underage Steven and is caught red-handed—twice—that Sheba sees Barbara also as a person with a fair share of skeletons in her closet. Cate Blanchett is riveting and poignant as the confused and guilt-ridden Sheba, who is likable to the audience even as she does unsavory things at the behest of a family at home. Still, Sheba does love her husband and children, and her infidelity is less about love and more an act of defiance against the life she has found herself in.

The interior monologues from Barbara's writings are deliciously spiteful and a joy to hear read by Dench. Besides the acting alone, they are the biggest pleasure of "Notes on a Scandal." The film moves quickly, stays conventional enough that it could bring in wide audiences if marketed correctly, and has a pounding music score by Philip Glass (2006's "The Illusionist"). It is also quite topical, playing on the whole student-teacher relationship taboo that always gets a lot of press and air-time on the news. "Notes on a Scandal" is made with taut precision, to be sure, but it is also over-the-top on occasion—Sheba's outrageous confrontation with the media camped outside Barbara's house gets a bad laugh—and admittedly follows a plot trajectory that is unoriginal and easily predicted. The last scene, set on a park bench, is a creative copout, too. Nonetheless, "Notes on a Scandal" is redeemed by a top-flight filmmaking team and two unblemished performances from fearless pros. Just to see Cate Blanchett bitchslap someone as honorable as Judi Dench is worth the price of admission.