The story takes place during the reign of Ivan III, who has set his mind on uniting the scattered Russian principalities into a single, powerful state. To achieve this goal, he invites “a people-child” to serve—overseas craftsmen. Among others, an architect and engineer, Aristotle Fioravanti, arrives in log-built Moscow, along with the doctor Anton Ehrenstein, brought up by his brother. Anton’s enemies—Muscovites—consider him a sorcerer and a non-Christian (“a foreigner,” “basurman”). Anton’s noble aspirations, and his love for a nobleman’s daughter, Anastasia, are crushed by the deep-rooted stubbornness. The situation is further worsened by court intrigues, in which Sophia Paleolog’s brother and the family of the Tatar prince are drawn.