Having gotten into a terrible car accident, by the will of fate, KGB major Dmitry Gordeev was transported to ancient Rus'. It's autumn 1222. There is very little time left before the Russian princes meet in the first battle with a previously unknown people. None of the princes believes about the possibility of war with the Mongols. Life goes on as usual: merchants trade, boyars feast. Rus' is being torn apart by civil strife. Only Dmitry Gordeev knows about the impending threat. By cunning he manages to convince and win over the Prince of Chernigov Mstislav Svyatoslavovich. Together they are trying to take measures to persuade the princes to meet the Mongols as a single army. But the princes are self-willed and everyone wants to defeat the Mongols themselves, gaining glory and gratitude from the people. Will a person from the future be able to change history and protect Rus' from centuries of slavery.