The book portrays the political situation of Europe in the later Viking Age, Andalusia under Almansur, Denmark under Harald Bluetooth, followed by the struggle between Eric the Victorious and Sven Forkbeard, Ireland under Brian Boru, England under Ethelred the Unready, and the Battle of Maldon, and then the Byzantine Empire and its Varangian Guard, Kievan Rus and its neighbors the Patzinaks - all before the backdrop of the gradual Christianization of Scandinavia, contrasting the pragmatic Norse pagan outlook with the exclusiveness of Islam and Christianity.

Orm and Rapp join a Viking party raiding England again after a brief period of peace in that area following the reconquest of the Danelaw in the mid-10th century by King Edgar, Ethelred's father.

Orm joins a party led by Thorkell the High in England and when he learns that Harald's daughter Ylva is staying in London, gets baptised and marries her.

In 1007, with Orm now forty-two, his brother Are returns from the east after serving the Byzantine Empire, bringing the news of a treasure ("the Bulgar gold") he had hidden.

Orm decides to travel to the Dnieper weirs in Kievan Rus for the gold, and together with Toke and the Finnveding chieftain Olof mans a ship.

But on their return they encounter an unexpected crisis at home - Rainald, the rather ridiculous failed German Christian missionary, had become a renegade, turned into a Pagan priest of the old Norse gods and the leader of a formidable band of robbers and outlaws, and causes great havoc before being finally overcome.

Following this final crisis and from then on, Orm and Toke live in peace and plenty as good neighbours, and Svarthöfde Ormsson becomes a famous Viking, fighting for Canute the Great.

The story ends with the statement that Orm and Toke in their old age "did never tire of telling of the years when they had rowed the Caliph's ship and served my lord Al-Mansur."

In essays, Bengtsson expresses disgust with "psychological realism" in the literature of his day where the thoughts and feelings of the characters are discussed explicitly rather than indicated by actions and outward signs.

Bengtsson in effect throws the Viking heritage back in the Nazis' face" [3] The 1964 British-Yugoslav film The Long Ships (starring Richard Widmark and Sidney Poitier) very loosely based on the book, retaining little more than the title (of the English translation) and the Moorish settings.

The play was held atop a giant constructed wooden stage resembling a crashed Viking ship with a dragon's head and was based on the second part of Bengtsson's book, after Røde Orm returns to Denmark with the bell.