Spoilers for this episode.
Before the army leaves Kattegat, Bjorn insists that he will command it. Ivar believes Ragnar intended him to lead, but Bjorn refuses to divide authority among the brothers or the other kings. Harald is also distracted when he encounters Ellisif, the woman whose promised hand helped drive his conquests. She has married another man, leaving him humiliated despite the power he has gained.
Ubbe marries Margrethe and agrees to share their relationship with Hvitserk rather than forcing her to choose between them. Lagertha presides over a human sacrifice for the expedition, killing a young earl during the ceremony. Bjorn and Astrid slip away together, and Lagertha later makes clear that she knows about their relationship. The army departs with these private tensions still unresolved behind its public purpose.
In England, Aethelwulf questions Ecbert's behaviour and asks whether his father loves him, without receiving the answer he wants. Aelle remains confident that he can defeat the approaching Vikings until he sees the size of their army. His forces are overcome and he becomes the brothers' prisoner. They force him to show them where Ragnar died, refusing his attempts to bargain for his life. Bjorn kills Aelle with a blood eagle as the brothers watch, completing their revenge against the man who ordered their father's execution.