Adultery is a game for two.

Ilya lives in Moscow; Nina lives in St. Petersburg. Ilya has a beautiful wife and a daughter; Nina's husband is an artist, and they have a young son. Nina occasionally travels to Moscow to see her partners in the publishing industry. Ilya sometimes comes to St. Petersburg on business. But more often they are in the train between St. Petersburg and Moscow just to see each other. Because they have an affair.