In the year 1218, the Danish king Valdemar faces war on the borders of his kingdom. To protect his young son and heir, also named Valdemar, he sends him to the bishop of Ravensburg, Erskil, for safekeeping and education. However, the bishop is actually a conspirator who seeks to seize the crown for himself, as many of the nobles are dissatisfied with the unprofitable wars. One day, while exploring the castle, the prince and a kitchen-boy named Aske overhear the conspirators' plans. They are discovered and pursued by the One-eyed Man, a feared mercenary who seeks revenge on the king for abandoning him on a battlefield where he lost an eye that was later eaten by an eagle, which he now shares his sight with.