On the eve of his wedding, whilst holidaying at Lake Annecy, Jerome, a career diplomat, accidentally meets up again with Aurora, an old, very close friend. Through her Jerome meets her landlady, Madame Walter, together with her youngest teenage daughter, Laura. Aurora tries to talk Jerome into a flirt with Laura, but he initially resists the tease. Jerome and Laura undertake a hike together in the mountains, and she develops a schoolgirl crush for Jerome which he finds increasingly difficult to resist.
A few days later, Laura’s attractive elder half-sister arrives, and Jerome proceeds to fall — not for Claire in her alluring bikini, but for Claire’s knee, which he irresistibly longs to touch.
However, Jerome controls his temptation. Eventually an opportunity presents itself during a boat trip on the lake when Jerome and Claire have to seek shelter in a hut from an approaching storm. Jerome tells Claire that he saw her boyfriend, Gilles, together with another girl. When Claire starts to cry Jerome consoles her by placing his hand upon Claire’s knee.