A spectacular, rousing epic adventure opens with the 200-man Viking army invading the small kingdom of Northumbria, the death of the English leader and the succession to the throne of the extremely sadistic King Aella (Frank Thring). His queen is pregnant and flees to a new land with her child. Years later, the child, now a young man (Tony Curtis), turns up as a slave in the Viking village. Unknown to both of them, Curtis is the brother of future Viking heir Kirk Douglas, and their is an immediate enmity between them. They clash in a duel. Tossed into a pit of giant crabs, Curtis is saved when his true identity is discovered. A new Viking raid rescues King Aella's future queen, Princess Morgana (Janet Leigh), and the presence of this beautiful princess, increases the hatred between Curtis and Douglas.