With his fathers friend, a nice cameo by Omar Shariff, he manages to find a bunch of Norsemen, just in time to hear about demons terrorizing a friendly king. He comes to ask for help for his father. He is the king and his kingdom is under attack. The name cannot be said. They may not name names with the monsters, but when the soothsayer says that 13 warriors must head north, guess who gets elected.
Old woman speaks and holds up a stone.
The 13th warrior is you. So away he goes. Banderas is fine, but gets a bit lost in this forest of giant blond men and their even bigger horses. Which makes for great battle scenes, many of them. And they are battling monsters who are pretty grim guys.