Blanche (Emmanuelle Chaulet) has recently moved to Cergy-Pontoise, a “new” prefabricated city in Paris suburb, to work at city hall. During a lunch break she meets the vivacious and immediately likable Léa (Sophie Renoir). Although she is not fond of sports, Léa agrees to go swimming with Blanche at the local pool. There they meet Alexandre (François-Eric Gendron), one of Léa's friends, along with Adrienne (Anne-Laure Meury), his current girlfriend. Blanche finds herself under the spell of the young engineer. Then Léa leaves for the holidays while Blanche stays in Cergy. By chance, Blanche bumps into Alexandre in the street. She clumsily tries to make a pass at him but soon she’s also bumping into Fabien (Eric Viellard), Léa’s boyfriend.