Jérôme (Jean-Claude Brialy) is a career diplomat who decides to spend July in his hometown on Lake Annecy in the French Alps before traveling to Sweden to marry his fiancée. He bumps into Aurora (Aurora Cornu), an old friend who is now a writer. She's staying at a house owned by Madame Walter (Michèle Montel), a twice-divorced woman with two teenage daughters, one of whom is out traveling. Jérôme meets one daughter, 16-year-old Laura, (Béatrice Romand, in her first of six Rohmer films), who visibly becomes infatuated with him. Later, Aurora discusses an idea for a novel she's had, about an older man who becomes obsessed with a younger girl, and noting Laura's interest in him, proposes that Jérôme act as a guinea pig to help her with the story, an idea he finds amusing enough to go along with.
Laura turns out to be articulate, precocious and charming, and Jérôme finds it a bit of a struggle to keep things platonic with her, before they finally realize they're Better as Friends. But matters are shaken up when her older sister Claire (Laurence de Monaghan) comes back home. A classically beautiful blonde, Jérôme finds himself drawn to her. But not really to her looks: he develops a fetish on her knee, and is sorely tempted to touch it. As the month goes on, Aurora observes both Jérôme's predicament and the two sisters as they experience their own romantic foibles.
This film contains examples of:
- Body Motifs: Jérôme doesn't really much care for Claire, except he cares very much for her knee.
- Brainy Brunette: Aurora and Laura.
- Dirty Old Man: Jérôme knows that he's dangerously close to becoming one.
- Dumb Blonde: Claire maybe isn't dumb, but is much more simple and naïve than Laura.
- Freudian Excuse: Laura admits that not having a father in her life is why she's attracted to older men.
- Jerk with a Heart of Gold: Jérôme carries on like a debonair ladies' man, but by the end we know that he does have a conscience.
- Scenery Porn: The French Alps and Lake Annecy play big supporting roles in the film.
- Secondary Character Title: Claire doesn't show up until 47 minutes into the film (she's talked about earlier, though) and just mostly stays on the sidelines until the final few minutes.
- She's Got Legs: Claire, of course.
- Talkative Loon: Vincent, Laura's sort-of boyfriend.
- Tomboy and Girly Girl: Laura is the Tomboy, Claire is the Girly Girl.
- Wise Beyond Their Years: Laura, who's smart and also quite self-aware.