The movie opens at the start of Delphine's summer vacation. Delphine has just suffered the breakup of a relationship and then her travel companion ditched her so that her new boyfriend can accompany her to Greece instead. She is left without plans at a time when Paris is emptying for the summer. Another friend invites Delphine to join a beach party for the weekend, but she finds that she's the only one amongst the group who is single so she quickly returns to Paris. Her family pressures her to spend the holidays with them in Ireland, but she resists. She travels alone to the Alps, but is put off by hordes of vacationers and turns around. Traveling restlessly, the theme of the movie (characterized by Roger Ebert) becomes clear: Delphine "is incapable of playing the dumb singles games that lead to one-night stands. She meets a new girlfriend, who flirts with two young men, and she flees in anger. She recoils from the pre-packaged lines of the guys she meets in bars and on trains. She simply cannot engage in that kind of mindless double-talk any longer. Beneath her boredom is genuine anger at the roles that single women are sometimes expected to play." While in Biarritz she eavesdrops on conversation about Jules Verne's novel Le Rayon Vert (The Green Ray). According to Verne, when one sees a rare green flash at sunset - our own thoughts and those of others are revealed as if by magic. At the Biarritz train station she meets a young man who is travelling to Saint-Jean-de-Luz. She goes with him and together they observe le rayon vert (the Green flash).