Twelve-year-old Anaïs Reboux and her fifteen-year-old sister, Roxane Mesquida, are enjoying a family vacation in the charming French seaside town of Les Mathes. Feeling restless in their vacation home, the sisters venture into town, engaging in a candid discussion about relationships and the complexities of their virginities. While the conventionally attractive Elena has explored her sexuality, she has decided to reserve actual intercourse for someone she truly loves. In contrast, the more self-conscious Anaïs yearns to lose her virginity to a man for whom she holds no emotional attachment.
During their outing, the two sisters encounter Fernando, an Italian law student, at a local café. Their meeting quickly escalates when Fernando sneaks into the girls' bedroom later, seeking a romantic encounter with Elena. Though Anaïs is awake and silently observes, the tension increases when Elena, after discussing Fernando's past relationships, initially consents to sex but then hesitates at the last moment. Overcome with frustration, Fernando resorts to various tactics to persuade her, including threats of infidelity. Ultimately, Elena finds herself coerced into an anal encounter under the guise of proving her love, despite the evident pain it causes her.
The following morning, as Elena prepares to see Fernando off, he boldly requests oral sex, leading Anaïs to interject, frustrated and in need of rest. On their next beach outing, while Elena spends time alone with Fernando, Anaïs retreats to the ocean, clad in her new dress, singing softly to herself. Later, reflecting on their cherished childhood memories, Elena reveals that Fernando presented her with an engagement ring at the beach. Anaïs, feeling a sense of unease, openly voices her skepticism about Fernando's true intentions. That night, as Elena loses her virginity to Fernando, Anaïs weeps silently on the other side of the room, engulfed in sorrow.
Things take a dark turn when Fernando's mother arrives at their vacation home, demanding the return of the ring that belongs to her, a piece from a collection of jewelry representing Fernando's past lovers. Appalled by Elena's relationship with her son, she hastily decides to head back home to Paris. However, fatigue sets in during their journey, prompting them to stop for a break. It is at this moment that tragedy strikes; a man attacks their car, shattering the windshield with an axe, resulting in a horrific scene where Elena is killed, and their mother is brutally assaulted. In a harrowing twist, Anaïs is abducted into the woods, where she endures a horrific experience. When the authorities arrive the next morning, Anaïs shockingly claims she was not raped, leaving a chilling conclusion to their devastating ordeal.
