What if you came home one day to find some weirdo living in your house? What if that weirdo, in a barely understandable language, explained that he was your son? But you knew for a fact you had no children. This is what happened to André and Laurence Prioux, a bourgeois couple, stylishly living in a quiet upscale suburb. Convinced they are victims of an error or a con man, André wants nothing to do with Patrick. But Laurence, faced with the inexplicable, suddenly becomes the mother she never was and welcomes with open arms this long-lost son, who sprung out of nowhere with his pregnant fiancée. And her dog. When a childless couple encounters family... Or makes it up.