Electrically attracted, two Parisian couples agree to swap partners in Cordier’s psychologically sharp and slyly sexy take on changing the rules. When Rachel (Marina Foïs) meets Vincent (Nicolas Duvauchelle), she is seduced by his frankness, and decides to arrange dinner with their respective spouses, Franck (Roschdy Zem) and Teri (Élodie Bouchez). The two couples barely have time to become friends before they fall passionately in love, keeping the secret from their children. But what ties them to each other is so strong that confusion starts to settle in, and the stakes grow crueler each day.