The two girls quickly become inseparable, and Laurent (who also adapted the screenplay, with Julien Lambroschini, from Anne-Sophie Brasme’s acclaimed YA novel) excels at pulling us into their intensely private world. But when Sarah is invited to join Charlie, her mom and some other family friends on a seaside holiday, subtle fissures begin to form in their airtight bond. At the sea, Sarah lusts wantonly after the older Esteban (who’s clearly more interested in Charlie’s mom), and then, just as quickly, shifts her attentions to a handsome young pilot, leaving Charlie in her chilly wake.