A ferocious battle between the Vikings and the Franks eventually comes down to Ragnar against Rollo. The outcome will seal the fate of the two brothers.
With one last chance to take Paris, Ragnar and his Viking troops take a daring chance. Ragnar asks Bjorn for a favor that could change the course of Viking history.
In Iceland, Ubbe learns the truth about Kjetill and has a difficult decision to make. Back in Norway, the battle against the Rus has had grave consequences. But reinforcements have arrived, and Bjorn has an idea that may yet save the day.