A couple takes on a homeless teenager. The trio forms a family-like community that seems to work extremely informally and without many regulations. But then the harmonic situation escalates as the boy falls in love with his "adoptive mother".

Two couples, undermined by frequent scenes, fall apart: the men, Richard and Bertrand, directors of an advertising agency, move into their office; soon Lucien, their main client and friend, suffering from the same afflictions, joins them in this new bachelor life. For their part, the women regroup and organize themselves: Victoire absorbs herself in her work as a decorator; Charlotte, long submissive to Richard's personality, raises her head and finds a job; as for Pascaline, she runs off with Tabard, her husband Lucien's groom, to start raising sheep. These three crises, combined with a series of twists and turns, bring unexpected results for each of the couples.

Three young students, who met on the train, arrive in Paris and decide to find accommodation together.