Pavel is an architect, the father of five children, and wants a sixth. And everything would be fine if it weren't for the terribly small apartment in which the heroes live. To solve the problem, Pavel is developing a residential complex project for large families. The developer likes the idea, but, alas, only as a way to attract attention, so the Gerasimovs will have to build the Ark themselves. They settle in the old house where Paul's ancestors lived. This choice turns life into a real adventure and reveals to them the power of a large, friendly family.