The Cossack border guards on the southern borders of the Moscow state take a Tatar messenger prisoner. During interrogation, it turns out that the messenger was carrying a letter to the Polish governor from Khan Janibek, which talks about the Tatar army’s joint campaign with the Poles against Muscovy. At the same time, Tsar Fyodor Mikhailovich begins a war for Smolensk, and there are no people left on the southern border. Understanding the complexity of the situation, Voivode Kobelev decides to resort to military stratagem. Through his nephew Janibek, he sends information to the Crimean Khan that the only ford across the border river will not be protected. He himself is building a fortress in this very place...