The opening scenes are those of fierce Norse warriors, landing on the shore of England pillaging and killing anything that stands before them. Vikings live for exploration and battle and they believe that a warrior dying a glorious death will gain immortality, as those left behind will forever remember his courageousness. With this mythical belief, the Vikings call upon their god to help them continually search for battle, fearing nothing as they envisage a way to enter Valhalla, the Vikings paradise.
The Vikings, worshipers of Odin, the god of war and death, try to conquer England, which at that time was a series of small, divided kingdoms. The film moves against the background of blood, love and hate. The first invasion depicting Norse savagery sees the Viking leader Ragnar (Ernest Borgnine) invade the English coast and pillage everything in his path. He murders the king and rapes the queen, who later admits to her confessor Father Godwin (Alexander Knox) that she is pregnant. Once the child is born and christened Eric (Tony Curtis) he is sent away for his own safety but is later captured by the Vikings and made a child slave, unaware of his true identity and background.
With the rightful King to the English throne dead, Aella (Frank Thring) the successor proclaims that the defences against the Vikings need strengthening and he will unite the kingdoms of Northumbria and Wales by marrying the Welsh princess Morgana (Janet Leigh). The unpopular king also turns upon his cousin Lord Egbert (James Donald) and accuses him of being an English conspirator, and has him thrown into prison for his betrayal and treachery. Once the princess has set sail from her Welsh coast she is kidnapped by Einar (Kirk Douglas) the son of Ragnar. The Vikings seize her ship, take her prisoner and plan to use her as a pawn with blackmail in mind against Aella. Einar falls for her and intends to keep her for himself, regardless of the King's plan.
Lord Ebert, sentenced to a barbaric slow death escapes with the help of Ragnar and silently returns to Norway in the long ships. Once home Ragnar is greeted by his son Einar who is instantly antagonistic to the Englishman. While showing Lord Egbert some Viking customs, Einar comes across a pair of slaves, one of whom is Eric. Apparently captured as a child, Eric has grown up among the Vikings and learnt their customs, but he and Einar become enemies when Eric turns his hunting hawk on him, scarring him severely on the face.
Eric stands trial and is punished by being cast into a rock pool to be eaten alive by giant crabs. Egbert notices a royal pummel-stone Eric wears around his neck and ask's him how he came by it. Aware that the Queen mother had placed such an adornment on her illegitimate offspring, he suspects the true identity of Eric.
With the help of Eric, Morgana and her Lady in waiting are able to escape back to England, but this only intensifies the hate between Einar and Eric, whom we have now come to realise are half brothers. Einar now prepares a strong Viking force in pursuit of Eric to gain revenge and recapture of his Viking queen. The film is depicted with all the visual grandeur of genuine backdrops, along with some stunning shots of the Viking ships in the fjords of Norway. Authentic castles and a formidable cast make this film an all time classic.