Betty.

Claude Chabrol hasn't been heard from much lately. Now he is back with Betty, based on a Georges Simenon novel. Betty, an attractive, 28-year-old, obviously affluent woman, sporting a strange look - is it hostile, preoccupied, weirdly detached, downright crazy? - finds herself, drunk on a terribly rainy night, in a homey bar in Versailles, where a kindly-seeming doctor has brought her for dinner. Yes, it was a pick-up in a Paris bar, and there is something odd about driving all the way to Versailles in a downpour to a place that offers only one main course. But Betty seems to need protection, and who better to give it than a respectable-looking, fatherly physician?

Sitting there in the warm, familial Hole (Le Trou), as the hangout sheltering all kinds of misfits is called, the doctor suddenly starts talking weirdly, and is about to do something very, very queer. The way the mood imperceptibly changes from the mundane to the bizzarre, the precise manner in which the night/marish infiltrates the commonplace, immediately proclaims the master, or masters: Simenon the novelist, and Chabrol the screenwriter-director. What in Woody Allen's film would have appeared preposterous, here seems only too easily and dreadfully believable.

A middle-aged habituee of the Hole, Laure, comes to Betty's rescue. She and the proprietor (who, it turns out, is her lover) get the by now quite drunk young woman out of the doctor's clutches, and Laure takes her to her suite at the posh Trianon Palace in Versailles, where she has been living for the last three years since her husband's death. She has one special thing in common with Betty: they both like to hit the bottle. Next morning, the two women start to communicate, even though Betty is extraordinarily vague or taciturn about certain things. It does emerge, though, that she has "sold her children."

What does this mean? It means that she loved but never intended to marry Guy, her rich young husband from a suffocatingly bourgeois family, in which Guy's mother, Mme Etamble, rules the terribly proper, terribly constricting roost. Whether such a softspoken, despotic matriarch can still thrive in Paris (Simenon wrote this some thirty years ago) I doubt, but the director makes you believe it by his sheer command of detail. Chabrol knows what artists know (and Woody Allen doesn't): if the tiny things ring true, the hard-to-credit big ones will sound no alarms.

Take the scene where Betty, having been caught in adultery within ear-shot of her children, is made to sign a contract whereby, in exchange for never seeing her two little girls again, she will be provided with a decent living for the rest of her life. In full family gathering, a lawyer dictates and she write: "I, Elisabeth Etamble ..." etc. etc. By force of habit, Betty writes "I, Betty." When the lawyer finally notices this, he takes the paper and slowly, deliberately, almost artfully, tears it into two strips (not four or eight pieces), and lets them float onto the tabletop. It is the quiet elegance with which he does it that breaks your heart.

After she has signed, and is about to leave this house, these lives forever, Betty approaches the door behind which her girls are sleeping to kiss them goodnight and goodbye. The very nice but mother-ruled Guy tells her no, this is out of the question. What gets to you is the sweetly reasonable way he says it (his heart isn't really in it): it's late, they are already asleep, what's the point? His considerate tone, as if he were merely correcting a slight lapse in grammar, gives you cold shivers. As does the docile expression with which, after a slight hesitation, Betty walks on - like a naughty, semi-contrite child being sent to bed without her dinner.

But the final wonder of the film is the personality of Betty, who is not just the victim she seems to be, but also a victimizer. There is something spectrally affectless about her as she goes around not connecting with people, repaying good with evil, being a pathological case. As Marie Trintignant superbly plays her, she is an unforgettably disturbing character, walking in a cloud of otherwhereness, yet somehow knowing, in that sleep-walkerish way of hers, where to stick in the knife. As Laure, Stephane Audran is equally fine, and the rest are not far behind. Understated and aristocratically poised (and with minimal background music), Betty is one of the most well-behavedly bone-chilling horror stories of all time.