Antoine and Laurent, old friends, spend their vacation in Corsica with their respective daughters: seventeen-year-old Louna and eighteen-year-old Marie. One evening at the beach, Louna seduces Laurent. Louna is in love, but for Laurent it was nothing more than a momentary distraction. Without revealing her lover's name, Louna confides in her father, who tries by any means to discover who his daughter's lover is. How long will the secret be able to be kept hidden?