Adolescent French suburban lower-middle-class nerd Marc Morel was happy being the teacher's pet and school representative in a Latin competition. Until he meets and instantly falls in love with fatherless semi-illiterate shop clerk and ditto-daughter Martine Pérez. As his overbearing father Robert feared, stripling hormones run wild at the expense of academic future-building, but paternal authority is overruled by 'young love', which even yields peer-acceptance. Cool big brother Christian, a photographer, tries a more understanding approach, but even that runs into trouble.

It’s summer in a small port town in Brittany. Isabelle (Pascale Rocard), who has just graduated from high school, comes to join her mother Micheline (Bernadette Lafont). Micheline is being courted by a beach boy, Maurice—whom everyone calls Doudoune (Bernard Menez). Isabelle soon begins a sweet romance with one of his friends, Pascal (Pascal Meynier). Meanwhile, her father (Michel Aumont) has stayed behind in Soissons, where he runs a medical laboratory, and is bored to death. Every weekend, he comes to spend 48 hours with Micheline and sometimes splurges a little extra in Paris, hitting on girls in nightclubs. Efforts that are not crowned with success. On the contrary, in Brittany, that ladies’ man Doudoune gets what he wants... But when the family man comes to join his loved ones, the blunders and misunderstandings multiply...