Kostya and Olya are teachers at a university. While on vacation at a sanatorium, Olya becomes infatuated with a more respectable man, Sergei. Kostya, unable to find a better way to return what was lost, decides to get closer to his daughter Sonya - this is the only way to be close to Olya again and try to talk to her. Sonya is not very interested in Kostya, but the idea of irritating her father at a dinner with his new passion seems very tempting to her: especially after he kicked out her boyfriend Max for "not being serious." So the husband and wife find themselves under the same roof in different couples.
