At first, one almost thinks that everything's fine. Three girls live in Lyon in an ambiance of shared happiness. Laure is the eldest sister, who runs the household as well as the tango school the father left them. Beatrice is caught up in economic success: she is wealthy, generous and therefore thinks herself indispensable. And then, there's Claire, the youngest, a pianist whose gifts remain unrecognized. She gets in everybody's hair, but everyone's fond of her, which is normal, she being the youngest. Each of the three sisters feels entirely indispensable to the happiness of the two others. They're happy with their lives, and heedless about what hits them: their father, Louis, turns up after an absence of 15 years. Suddenly, it's every girl for herself. Each of the sisters must deal with her dependence, her resemblance to this often hated father. Once again, they must endure the mark of a man, this father who's only passing through. Troublemakers are always just passing through. It's more amusing for them that way...