In the late tenth century, young Red Orm is snatched from his Danish home by a Viking crew and set to the oars of their dragon-prowed ship. His travels sweep him from Moorish Spain to Irish monasteries and the Russian steppe, in a sprawling, saga-shaped adventure of a hero's long, eventful life.
Coastal people lived in villages so that no family depended only on its own catch, and so they could defend themselves against raiders. Those raiders came ashore in spring to stock up cheaply before a voyage, and in winter when they returned empty-handed from failed wars. Pooling both food and defence spreads the risks no single household can carry alone.
Plunder strips a coast so thoroughly that nothing worth taking remains, and the raiders must sail ever farther to find new prizes. Where many villages once thrived, only traces of old buildings are left. The raiding life keeps pushing its own frontier outward.
In this world every threat has its answer: a man can be beaten by a man, a weapon by a better weapon, angry gods by sacrifice, witchcraft by counter-magic. Bad luck alone has no answer. That is why luck ranks above strength and skill at arms in a man's list of what he needs.
Among foreigners, the most useful thing a man can have, after luck, strength and skill with weapons, is the ability to learn their language. Fighting wins you a place, but speaking their tongue is what lets you live among strangers. A seasoned traveller ranks it just below the things that keep him alive.