Usurper Sligon (Primo Carnera), a worshipper of the old List of Germanic deities, along with other rebel Vikings, have forced into exile the Christian royal family of the Viking kingdom of Scandia: King Aguar (Donald Crisp), his wife, and their son Prince Valiant (Robert Wagner). Aguar and his family come under the protection of King Arthur (Brian Aherne). When Valiant has grown to a man, he is sent to Camelot to undergo training as a knight under the tutelage of Aguar's family friend, the noble knight of the Round Table, Sir Gawain (Sterling Hayden).