Antoine and Laurent, longtime friends, are on holiday in Corsica with their daughters, Louna, who is seventeen, and Marie, who is eighteen. During a night at the beach, Louna entices Laurent into a romantic encounter. While Louna falls for him, Laurent sees it as a fleeting indulgence. Louna shares her secret with her father but keeps her lover’s identity hidden. Determined to uncover the truth, her father embarks on a quest to find out who his daughter’s mysterious lover is. How long can this secret remain undiscovered?