In Leningrad Alexei Zakharzhevsky comes to the family of his uncle-academician. He was born and raised in China, went through the camps and now rehabilitated. The academician and his young wife Ada meet Alexei at the station and arrange a gala dinner. Ada's mother, Anna Davidovna, a hereditary witch, looks at the guest on the first evening: they need an heiress to pass the sorcerous craft. Can Alexei become the father of a future sorceress?