Many legends go around the library of Ivan the Terrible. Many are looking for it, many have long been disappointed and stopped looking, and many consider it just a beautiful fairy tale. But the special services have always shown interest in beautiful fairy tales. They are constantly looking for at least some confirmation that the fairy tale is not really a fairy tale, but a reality. This time, the special services receive information that in Aleksandrov, the ancient capital of the oprichnina, traces of the library of the first Russian Tsar, lost for centuries in Liberia, and Alexei Pavlovich Meshcheryakov are sent in search of these traces, giving him an old friend, Captain Antipova Veronika Lvovna, as a partner. Thus, instead of retiring and returning to his hometown, the colonel has to go to Alexandrov, and from there fate throws him, together with Veronika and in the ancient capital - Aleksandrovskaya Sloboda, where they meet with the Terrible Tsar, his guardsmen and the young prince.