The French teenagers in Water Lilies would probably find the loquacity of their American counterparts rather gauche. In fact, in writer-director Céline Sciamma’s feature debut, the mostly female characters hardly talk at all. Instead, they ache. And doubt. And yearn. It’d all be très dull if it weren’t for the magnificent faces of Pauline Acquart and Adèle Haenel, who play new friends during a period of adolescence when beautiful girls are both sensual but still childlike. Actually, it still gets dull, even if at times the film skirts kiddie-porn territory.

At the beginning of the film, Marie (Acquart) spends her time going to synchronized-swimming meets in suburban Paris and trying to pump up her tomboy arms while goofing off with her best friend, Anne (Louise Blachère). You assume, at first, that Marie is really into synchronized swimming, especially when she approaches teen-queen Floriane (Haenel) and promises that she’ll owe her one if she can come to the pool as Floriane’s guest. But Marie is actually really into Floriane, and it’s hard to blame her: Floriane, even at a mere 15, drips sexuality, with long blond hair, Angelina lips, and sleepy, seductive eyes. The other girls hate her and assume she’s a slut.

She is, at the very least, a bitch—though she first refuses Marie’s overtures, she later decides she can use her as an excuse to go make out with her boyfriend, François (Warren Jacquin). This pains Marie for two reasons. For one, Marie is so caught up with this girl that she steals her garbage. And the chubby, self-loathing Anne is crushing on François as well, though Marie cares less and less about Anne and her “childish crap” as she gets closer to Floriane and glimpses the adult world. Increasingly, Floriane leads Marie on, even asking her to take her virginity so no boy will find out the truth about her bad reputation.

Through Water Lilies often plays like an ethereal Mean Girls—water imagery, languid close-ups, and silence dominate, with only spare music near the end —Floriane’s motivation is frustratingly unclear. A late-chapter shot shows her dancing lustily around boys after just as passionately kissing Marie…but is she cruelly leading Marie on or just playing a part? It would seem more likely that she’s happily experimenting, but the images that Sciamma chooses to surround Floriane (guys jumping around with underwear on their heads, Marie and Anne contentedly floating in a pool) suggest the message is that men are dumb and Floriane is toxic. Ultimately we’re left with a story that’s prettier than it is substantive, with an open-endedness that doesn’t provoke as much thought as you imagine the director intended.