Unexpectedly, the son of a Novgorod nobleman, Istoma Yakovlev, had to go on the run in order to escape the wrath of the all-powerful noblewoman Martha Boretskaya, who destroyed his entire family: his parents, two younger brothers and a baby sister. Fate brought the fugitive together with an artel of buffoons, and not ordinary ones. They turned out to be spies for the Grand Duke of Moscow Ivan III Vasilyevich, who had disagreements with the Novgorod boyars. Young Istoma vowed to avenge the murder of his family on the boyar Marfa Boretskaya (who was nicknamed the Posadnitsa for her great power over Veliky Novgorod) and therefore undertook, under the guise of a buffoon, to find out her plans.