Valentin D. and Constance Brandt, a couple of fashionable architect-designers are preparing the opening of their retrospective at the Palais de Tokyo. But what nobody knows is that, to integrate into the world of Parisian design and luxury, Valentin lied about his proletarian and ch'tis origins. So when his mother, brother and sister-in-law arrive at the Palais de Tokyo by surprise, on the opening day, the meeting of the two worlds is shattering. Especially since Valentin, following an accident, will lose his memory and find himself 20 years back, more punished than ever!