Pensioner Sergei Ivanovich works in the local history museum of a provincial town in central Russia, where he lives. From time to time he travels to the wilderness of the region in search of antique things. On one of these trips, luck smiles at Sergei, he finds a real runestone. However, instead of world fame, a series of mystical events occurs, as a result of which he finds himself in the same place, but... in the past, in the body... Yes, he himself does not know which one. The hero will have a struggle for survival and "implementation" in local realities. Sergei wants to find out who he is, to solve the riddle of runestone. Will it cope? In Russia it is 1339. In the Northeast, and in Ryazan, endless intrigues and undercover games of princes for the coveted label. The Golden Horde is stronger than ever, and the Grand Duchy of Lithuania is like a skating rink, one by one crushing the southern and western Russian principalities.