Liliane and Maud are twin sisters. The first is a modest provincial hairdresser while the second leads the great life in Paris. They both fight over their mother's custody.
A couple since high school, Charlotte and Adam have just had their first child. But they're not happy, and habits are gradually replacing enthusiasm, to the point of driving them apart... Hoping to recapture the momentum of their early days, they decide to become guinea pigs in a revolutionary treatment designed to strengthen their bond and desire.