On the eve of the greatest battle of the medieval period, William the Duke of Normandy is on the English coast to regain a land he believes belongs to him. He is here to fight his brother-in-law, Harold II, King of England. As William waits for the right moment for battle, he meets Vidr a mysterious wayfarer, who invites him to accept a ritual game of Claang; a gladiator game very similar to chess. As he recounts the legendary origins of this game, Vidr narrates the story of Tyr, an ancient leader, who like William, is about to risk everything in battle that all believe to be impossible to win.