The series introduces us to the brutal and mysterious world of Ragnar Lothbrok, a Viking warrior and farmer who yearns to explore—and raid—the distant shores across the ocean. His ambition puts him at odds with local chieftain Earl Haraldson, who insists on sending his raiders to the impoverished east rather than the uncharted west. When Ragnar teams up with his boat builder friend Floki to craft a new generation of intrepid ships capable of conquering the rough northern seas, the stage is set for conflict.