Junon (Catherine Deneuve) and Abel (Jean-Paul Roussillon) are the parents of three grown children: Elizabeth (Anne Consigny), a melancholic playwright with a mathematician husband (Hippolyte Girardot) and a tortured teenage son, Paul (Emile Berling); Henri (Mathieu Amalric), the self-destructive black sheep, banished from family events by Elizabeth five years prior; youngest Ivan (Melvil Poupaud), the peacemaker, is married to the beautiful Sylvia (Chiara Mastroianni) and has two eccentric little boys; while a fourth Joseph, the eldest died from leukemia as a boy. When the disease reappears again in the family, all are tested to see who can be a donor, and then everyone including lovesick cousin Simon (Laurent Capelluto) and Henris girlfriend, Faunia (Emmanuelle Devos) return home for a long Christmas weekend. All crowded again under the same roof, solidarity quickly and hilariously devolves into feuding, drunkenness and bed-hopping, as everyone struggles to make sense of the mysteries of family, life, and what lies ahead.