Cheated on and fired from her job, Lucille leaves her suburb and moves to Paris with little hope of finding anything better. Shortly after arriving, she saves a desperate man from drowning. Pierre is also cheated on, but in terms of work, he is better off than Lucille: co-president of a large company, he lives in a luxurious apartment overlooking the Seine. To thank his benefactor, he offers her a place to stay for the night... This situation suits Lucille just fine, and she decides to stick around. Pierre is not at all pleased, as he finds the young woman to be a disaster, with manners that are too "common" for his taste, and who never misses an opportunity to put her foot in her mouth... The beginning of a turbulent and conflictual relationship. Will love conquer social differences?