Vincent Machot knows his life by heart. He shares it between his hair dressing salon, his cousin, his cat, and his too-invasive mother. But life sometimes holds surprises, even for the most prudent of people... He crosses paths with Rosalie Blum by accident. She is a mysterious and solitary woman whom he is sure he has already met. But where? Intrigued, he decides to follow her everywhere, in the hope of knowing more about her.