On paper it seems impossible. A film with two strong female roles that are complemented by knockout performances? It can’t be!

Dame Judi Dench, who has established herself as one of today’s most consistent actresses, and Cate Blanchett, who is similarly established, deliver solid performances in the deliciously devious Notes on a Scandal, based on Zo? Heller’s novel of the same name.

The film is seen through the eyes of world-weary history professor Barbara Covett (Dench) as she meets the new kid in town, the dreamy art teacher Sheba Hart (Blanchett). For those in the audience who aren’t biblical scholars, Sheba is a derivative of Bathsheba, the woman who, in the Old Testament, wooed King David from afar.

Let’s just say Sheba comes by her name honestly. Her husband (Bill Nighy) is several decades older than she, and she first knew him as Professor Hart. Even as a married mum, Sheba is undeniably charismatic. She exudes a playfulness that attracts legions of female friends and a radiance that beguiles scores of married men. Hard-boiled Barbara is initially perplexed by Sheba’s naivet?, but eventually falls under her spell after the two share a couple cups of coffee and a dozen deep secrets.

It is soon evident that Barbara has more in mind for their relationship than casual nods in the hall and the occasional obligatory greeting she gets from the rest of the staff. Barbara pushes herself into Sheba’s life and begins to mark her territory. She writes extensively in her diary about their bond and becomes highly possessive of her new charge at school.

When Barbara sees the conflicted Sheba in the throes of passion with a 15-year-old student, she reacts as both a betrayed friend and an eager detective who has just hit the jackpot for emotional blackmail.

Barbara lords her secret knowledge over Sheba’s head, using it to draw Sheba further into her web. As you might suspect, Barbara can be a little temperamental at times and isn’t the best at keeping secrets.

Seeing Notes on a Scandal is like going on a roller coaster: You can see all of the loops, dips and turns before you even get on, but the ride is still a thrill.

Notes’ trailer certainly doesn’t try to keep Sheba’s ultimate fate a secret, but watching the film from the beginning is still enjoyable, thanks in no small part to Dench’s and Blanchett’s full throttle performances (performances that got them well-deserved Oscar nods as lead and supporting actress, respectively) and bewitching direction from Richard Eyre.

Blanchett’s role is a rich one. It would have been easy to portray Sheba as a disinterested waif who falls into a clandestine affair and allows herself to be manipulated by the boy and Barbara. However, Blanchett gives Sheba the complexity she deserves. This is a woman desperate to make a difference in the world.

When a young man willingly plays the part of her apt pupil, she is swept away with amazement and repays him the way she once repaid her professor-turned-husband. She is ashamed, enamored and vulnerable. When Sheba’s adolescent Lothario gives her a final kiss-off, her pain is tangible. This was no fling for her; it was validation.

The real star, though, is Dench, who sinks her teeth into this meaty role and never lets go. She embodies the life of her character: A worn-down professor who has reached the autumn of her years without much to show, save for her diaries and a handful of “gold star days.” She slips into the role of the sinister spinster so well that she makes blackmail, betrayal and deceit seem like essential aspects of any friendship. Her role is a difficult one to play, and a lesser actress might have resorted to camp and melodrama. But Dench makes Barbara’s every move seem authentic. Dench imbues Barbara with a quiet desperation that is familiar to almost anyone. This increases her character’s creep-factor considerably.

There are more than a couple of hints that Barbara is sexually attracted to Sheba, but I think that sexual attraction is just the tip of the ice-maiden iceberg. Barbara may very well be a lesbian, but the fearless focus that Barbara gives her obsession with Sheba suggests a deeper truth. She has become isolated by loneliness and even the suggestion of companionship sets her on the warpath. While voluntary friendship is fine, coersion is just another way to ensure she gets what she wants.

While watching, I was reminded of The Talented Mr. Ripley (which features Blanchett in a supporting role), another film that encourages its audience to revel in the sinister motives of its protagonist. As with Tom Ripley, we watch with glee as Barbara’s plan unfolds, and when it reached its masterful crescendo, I was giddy.

Finally, here is a full-bodied drama complete with hypnotic female characters that is fun to watch, too! So what if it’s predictable? It’s still one hell of a ride.