Spending her summer vacation at a family beach house in Normandy, 15-year-old Pauline seeks to experience her first taste of love and romance. Accompanied by her older cousin Marion, a recently divorced and philosophically-minded beauty, Pauline observes Marion's complex relationships with men, taking mental notes for her own nascent love-life. Marion reconnects with an old flame, Pierre, who is unabashedly infatuated with her; however, she appears more intrigued by the candid and spontaneous Henri, whom she meets at the beach—a man who claims to value honesty and freedom in affairs of the heart.

Amidst the gentle rhythms of the seaside and casual beach outings, a web of attractions and rivalries begins to unfold. Pauline, curious and quietly perceptive, navigates her own feelings of attraction when she meets a local boy, Sylvain. Meanwhile, Marion, Pierre, and Henri become entangled in a dance of desire and deceit, each projecting their own romantic philosophies and seeking fulfillment. As the summer wears on, the characters engage in conversations that reveal their contrasting views on love, commitment, and honesty, which in turn fuel the dynamics of their relationships. Pauline's observations and interactions with these adults become a subtle coming-of-age journey for her as she witnesses the complexities of adult romantic relationships first-hand.