From the video blurb:
The Novgorod prince Alexander is loved by simple people, but has also many opponents. Huge mongolian army of Batu Khan threatens with invasion from the south. The Swedish knights plan a crusade to Russia and transfer the spy to Novgorod. Nobles opposition prepares for murder of Alexander, and has the plan of treachery of city. In completion to everything, the best friend to prince Ratmir has loved a princess and now can become for Alexander the dangerous enemy. Prince is young, but the life demand from Alexander - military valour, foresight of the diplomat and deep wisdom.