Maurice Pialat's "A Nos Amours" has a dark and obsessive power, a rawness that's frightening. Pialat isn't wistful about lost innocence -- far from it. His movie teems with rot, so that the familiar tale gains a new immediacy; with the presence of Pialat himself in a leading role, the movie has the bedrock recklessness of a public confession.

The movie focuses on Suzanne (Sandrine Bonnaire), a beautiful 16-year-old just discovering her sexual power; she throws over her boyfriend, Luc (Cyr Boitard), and starts to sleep around. Her father (Pialat), a furrier, abruptly leaves her mother (Evelyne Ker), who waxes hysterical over her daughter's promiscuity; her brother (Dominique Besnehard), taking over as head of the family, thrashes the girl repeatedly.

On the surface, "A Nos Amours" has the pat sociological morality -- "divorce, child abuse, girl in trouble" -- of a TV movie; until it starts to work on you, you half expect Dennis Weaver to pop up, looking troubled. But it doesn't feel like a TV movie; the improvisatory raggedness of its scenes is a tip-off that something more is afoot. Pialat has invested "A Nos Amours" with a metaphysical weight -- the characters experience the action as a parable of the Fall, each in his own vocabulary. Suzanne laments not being 15 anymore; the mother is wracked with hatred of her own procreation; and toward the end, the father intones, "When you've always believed these things and you suddenly discover they're not true, a gulf opens."

What fascinates Pialat, though, is not the loss of innocence as a concept, but rather how this pessimism is transferred from parents to children, the emotional mechanisms of family life. In the universe of "A Nos Amours," a loveless marriage replicates itself, in the next generation, as an insatiable hunger for love. Beneath all of this lies incestuous desire, which thrums through the movie like a resonant bass chord. The brother persistently leers at his sister, remarking on her beauty and even how good she smells; the father admits to the same feeling, although more honorably and obliquely; the son replaces the father in the affections of the mother.

Pialat's technique is naturalistic; as he actually enters the action, the movie almost seems directorless. Bonnaire has the ferocious nubile appeal of sexuality that just emerged yesterday, and she knows it; as she seduces her parade of lovers, she's found a tool to get even. But in a story that is, more than anything, about a father and daughter, she shifts gears when she's along with Pialat, becoming engagingly genuine and mock-conspiratorial.

"A Nos Amours" isn't an easy movie -- the construction can seem meandering, and there's hardly anything "entertaining" about it. But it makes connections between characters and themes that are rarely seen in film, and makes them seamlessly. For Pialat, sex is an endless, doomed rondo; men destroy women, women destroy men. "A Nos Amours" (ironically, "To Our Love") finds the horror of sex at its most salient -- at the point of first bloom. In a film culture where the loss of virginity is just a joke to be endlessly replayed, you can't help but be wowed by it. A Nos Amours, opening today at the Circle MacArthur, is rated R, and contains nudity, sexual situations and violence.