In Paris in the early 1960s, Ronald is a son of a good family, with a carefree, pleasure-oriented life. He is one of the leading figures in the small world of Saint-Germain-des-Prés. Following a trivial parking incident, he meets Arthur, a young man with a straight face who hurts his pride. It is at this moment that Ambroisine, a beautiful young woman, appears... she will be the instrument of Ronald's revenge.