Blanchett plays Sheba Hart, a new teacher at a British private school. She meets and forms a professional friendship with Barbara Covett (Dench), a veteran teacher who doesn’t put up with any guff from the students. Barbara tries to toughen Sheba up a little bit, encouraging her to be more of a disciplinarian and less of a friend to the kids. There’s actually something quite condescending about the way she does it; the older teacher clearly disapproves of how soft-hearted the newbie is.

There is probably no way to really talk about Notes on a Scandal without giving away the event that puts the plot in motion, but I’m going to try anyway. Although this twist is generally revealed in the advertising, I didn’t know it as I sat down to watch the movie prior to its release. For the benefit of those who may not know what happens, I’ll attempt to preserve that surprise, even though it means leaving out discussion of a significant character.

One evening, Barbara catches Sheba in a very compromising position, one that horrifies her to the very core. When the younger woman finds out that her secret has been discovered, she braces herself to be ruined. But Barbara doesn’t do that. Instead of turning her colleague in, she offers to keep the secret. Her actions do not spring from generosity, though; instead, she acts out of manipulation, knowing that, armed with this knowledge, she can get Sheba to do whatever she wants. Barbara is the ultimate control freak – the kind of person who will shamelessly toy with others in order to make the world “right.”

The suspense comes in as Sheba slowly realizes she’s being used. On one hand, she wants to confront (and stop) her tormenter. On the other, doing so would result in her secret being revealed. One of the best things about Notes on a Scandal is that it finds a realistic solution to the story. Most psychological thrillers usually resolve things with a murder. (Call it Fatal Attraction Syndrome.) Typically, the villain is killed righteously by the hero (or heroine). This story, written by Patrick Marber (Closer) and directed by Richard Eyre (Iris), avoids that kind of clichéd conclusion. The situation comes to a steam, things happen, and life goes on for everyone. Life may never be the same, but it goes on. The film is much smarter for finding an ending that feels like real life.

Because it ends on an authentic note, we’re left to ponder the things that are really disturbing in the story. Notes on a Scandal is all about the art of the power play. Barbara is a sad, lonely, uncompromising woman. She’s the sort of human being who seems to have some sick need to control others. There are little suggestions about why she’s so over-involved in her colleague’s life, but the important thing is that she appoints herself as a moral arbiter who takes matters into her own hands for selfish reasons. Watching the movie, you don’t always know whom to root for – and that’s a good thing. You kind of feel sorry for Sheba, yet at the same time, it’s impossible to condone her actions. But it’s hard to look at Barbara’s behavior as acceptable. Notes on a Scandal dissects the issue of morality in a way few films dare to, and it concludes that there will always be people out there who are willing to do immoral things in the name of being morally superior.

This is very much an actor’s showcase, as the two leads have lots to work with. Blanchett, often cast as a strong woman, effectively plays against type as the impulsive, confused Sheba. Dench, meanwhile, is brilliant as the scheming, conniving Barbara. In fact, she’s one of the most realistically evil movie characters in a while, because her evil is based in very human qualities. What’s great is that Dench completely shows us the motivations of her character. We may not agree with what Barbara is doing. It may even appall us. Yet we always understand why she’s doing it. Dench takes all the woman’s convoluted thinking and brings a twisted sense of clarity to it. The best antagonists are the ones who make sense on their own sick level, and that’s exactly what Barbara is.

Notes on a Scandal puts a lot of other psychological thrillers to shame. It’s smart enough to keep the focus on the “psychological” part and go lighter on the traditional “thriller” elements such as chases, shootouts, and fistfights. Besides, it doesn’t need those things. The movie knows quite well that the life of an ordinary person can be thrilling enough. This is a tense, terrific film.

( 1/2 out of four)

Notes on a Scandal is rated R for language and some aberrant sexual content. The running time is 1 hour and 34 minutes.