By LISA NESSELSON

The painfully spot-on essence of teen angst meets the spirit of Esther Williams in "Water Lilies." First film by gifted scripter-helmer Celine Sciamma nails the aching doubts and offhanded cruelty of 15- and 16-year-old girls. Outstanding lead trio of young thesps wrestle with friendship, heterosexual and same-sex crushes and the queasy drumbeat of nascent sexuality. Probing and impressively assured fest-ready gem is brimming with talent to watch.

Pic has meaningful subtext galore but offers straightforward pleasures as an almost frighteningly perceptive portrait of how hard it is to be a girl in the exploratory phase en route to womanhood. Be it pretty lasses or their ordinary-looking peers, male viewers can rest assured that this is an accurate take on distaff disarray.

It's summer and the vast municipal swimming pool is one of the main social centers in the 1960s-built Paris suburb of Cergy, where film is set.

The girls' synchronized swimming team does well in regional competition. Floriane (Adele Haenel), a shapely blonde with come-hither looks, is a valued performer. The other girls don't like her but men and boys certainly do.

Marie (Pauline Acquart), who isn't on the team, is small for her age and flat-chested. She becomes Floriane's confidante and cover for the budding siren's assignations, often at the expense of Marie's best friend, Anne (Louise Blachere).

Big-boned, girlishly chubby Anne stands out among her trim and far daintier classmates. She's self-conscious about her body but forthright and outgoing, whereas Marie is almost creepily reserved.

Anne has a crush on male swimmer Francois (Warren Jacquin), but Francois only has eyes for Floriane.

The girls play emotional chess as they make their moves, hoping to get what they think they want although their desires are as new as they are incessant.

A contempo film about teens without a cell phone in sight is refreshing and gives pic a timeless quality. Parents and other authority figures are so tangential that the middle-class 'burb could be called No Adult Supervision.

From a memorable conversation about the ultimate significance of ceilings, to a novel technique for shop-lifting, to a game that involves storing water in one's cheeks, pic takes the pulse of the silly side of adolescence. But at its core, Sciamma vision on girl-to-girl sexual rituals is as profound as it is rare on screen.

French title means "Birth of Octopuses." Underwater shots of the young swimmers' paddling legs certainly look like flailing marine life. The amount of effort to keep one's smiling head above water while churning prevails below the waist is apt indeed.

Camera (color), Crystel Fournier; editor, Julien Lacheray; music, Para One; production designer, Gwendal Bescond; costume designer, Marine Chauveau; sound (Dolby), Pierre Andre, Daniel Sobrino; assistant director, Delphine Daull; casting, Christel Baras, Laure Cochener. Reviewed at Planet Hollywood, Paris, April 28, 2007. (In Cannes Film Festival -- Un Certain Regard). Running time: 85 MIN.