Redbad is having doubts about the old-fashioned, pagan rituals of the Frisians, also known as ‘the free folk’. He clashes with his father when his girlfriend Fenne is chosen to be sacrificed to the gods. During the sacrificial ritual, the Franks attack and the Frisia lose their town Dorestad. Redbad’s uncle Eibert makes a swift bid for power and blames Redbad for their defeat and his father’s death.

Tied up on a raft, Redbad is pushed out to sea to die. But Redbad manages to survive the journey and washes up on Viking shores. There, he learns the value of his own culture. He is slowly accepted into the clan, and after fighting with the Vikings against a rival clan of Norsemen, he marries King Wiglek’s daughter. When he and his wife return to Dorestad, he discovers that his sister has been married off to the son of Frankish King Pepin of Herstal. At a fair, he sees Willibrord the priest force his sister to convert and humiliate her in public. He swears he will set her free. He cannot do this alone, but his uncle and nephew, who are now in power, do not seem to have an army powerful enough to defeat the Franks.