`CRUEL INTENTIONS' A STEAMY BET.

Byline: Bob Strauss Daily News Film Critic

At least Sarah Michelle Gellar and Ryan Phillippe, the stars of ``Cruel Intentions,'' don't act like the kids in all the season's other teen movies. They don't act like kids who ever lived on planet Earth, either, but that somehow seems appropriate for this bizarre, adolescent fantasy update of the 18th-century French novel ``Les Liaisons Dangereuses.''

Gellar and Phillippe, together again after the rather less rarefied ``I Know What You Did Last Summer,'' are the brilliant, decadent, sexually superpowerful Kathryn Merteuil and Sebastian Valmont, roles played by the much more mature likes of Glenn Close, John Malkovich and Annette Bening in ``Dangerous Liaisons'' and ``Valmont'' 10 or more years ago.

But instead of bewigged Gallic aristocrats, this time around they're filthy rich New York brats, a stepbrother and -sister whose negligent parents are never on a continent near enough to provide supervision.

So these two bratty arguments for eating the wealthy spend their time plotting to ruin the daughters of Manhattan's rich and obtuse. Sebastian can apparently seduce any female on two legs, despite the fact that he has all the personal magnetism of an effete lemur. Once he compromises a young lady, the calculating Kathryn - Gellar plays her like a highly sophisticated android programmed purely for wickedness - secretly ensures that the girl's reputation is shattered in the most embarrassing of manners.

Ludicrous as this stuff sounds in 1999, adapter-director Roger Kumble has shrewdly placed the action in one of the few settings where it could conceivably still matter: the world of Eastern-establishment debutantes. He also gets rich satiric fun out of one particularly twitty family - a dumb trust-fund bunny named Cecile (played in a marvelous state of emotional slapstick by Selma Blair) and her pretentious mother named, um, Bunny (Christine Baranski, to the manner born).

Cecile is so charged-up by her supposed degradation at Sebastian and Kathryn's hands, she subversively, if cluelessly, exposes their machinations for the ridiculous nonsense that they are. Somewhat disappointingly, though, this otherwise smart, wicked movie takes one of those schemes much too seriously.

If you're familiar with any ``Liaisons'' incarnation, you know the main plot springs from a wager Kathryn makes with Sebastian. If he can conquer an egregiously virtuous virgin - in this case, school headmaster's daughter Annette Hargrove (Reese Witherspoon), who's written one of those ``Why I'm saving myself for true love'' essays in Seventeen magazine - she'll reward her stepsibling with the one woman he could not have: herself.

If he doesn't accomplish his task, Sebastian forfeits the keys to his '56 Jaguar convertible. Of course, an even worse fate awaits the fancy lad: He truly falls in love with the genuinely good Annette.

Bad melodrama ensues, but despite the arch, starched tone that dominates the film, some real emotional impact builds.

Parents - and their adolescents whom the film is clearly targeting - will want to know just how dirty this thing gets. The answer is: just a tad, in every way but verbally. The only nudity is a funny shot of Phillippe's backside, the only sex is a discreet and loving scene between him and Witherspoon (who are engaged in real life, no less), and Cecile's erotic awakenings are played purely - and expertly - for laughs.

Some of the things that come out of the mouths of these babes are, however, certifiably shocking. After hearing just how Kathryn proposes her wager to Sebastian here, whenever Gellar stakes out a vampire as TV's ``Buffy,'' it will have a whole, prurient new resonance.

That, like everything else about ``Cruel Intentions,'' is in no way good for children and other living things. But they'll probably like it anyway.

THE FACTS

The film: ``Cruel Intentions'' (R; language, sex, nudity, violence).

The stars: Ryan Phillippe, Sarah Michelle Gellar, Reese Witherspoon, Selma Blair, Louise Fletcher, Christine Baranski and Joshua Jackson.

Behind the scenes: Written and directed by Roger Kumble, based on Choderlos De Laclos' novel ``Les Liaisons Dangereuses.'' Produced by Neal H. Moritz. Released by Columbia Pictures.

Running time: One hour, 37 minutes.

Playing: Citywide.

Our rating: Three stars.

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Photo

Photo: Kathryn (Sarah Michelle Gellar) and Sebastian (Ryan Phillippe) play conniving step-siblings who make a wager in ``Cruel Intentions.''