The film is set in Moscow, nowadays. The center of events is the miraculously preserved world of a communal apartment – one of the last in our time. It remains almost the same order as it was decades ago – a corridor filled with things, disputes and sometimes squabbles between neighbors, the eternal dream of a separate apartment or at least an expansion of living space. But this is only at the beginning. With the advent of two new tenants, the relationship of neighbors changes, and the apartment itself becomes not just a communal apartment, but a real detective agency. But, everything is in order.