Full episode spoilers.
Horik returns to Kattegat after the defeat in Wessex and presses for another expedition. Ragnar wants news of Athelstan, but Horik offers little comfort and dismisses the missing man. The leaders lack enough ships and warriors for their plans, so Horik proposes restoring the alliance with Borg. Rollo carries the invitation, presenting cooperation as more useful than revenge, and Borg accepts the chance to return to Kattegat.
Lagertha faces Sigvard's anger after arriving home without Bjorn. Men attack her in her bedroom and leave her badly beaten, but Sigvard continues humiliating her at a feast. When he tries to expose her body to the hall, she stabs him in the eye. Another man then beheads him. In Wessex, Ecbert privately shows Athelstan Roman paintings and manuscripts, asking him to study the surviving writings while keeping their work secret.
Borg's welcome proves to be a trap. After the feast, Ragnar's men burn the building holding Borg's warriors and seize Borg from his room. Rollo prevents an attack on Borg's pregnant wife, but Borg himself is beaten and dragged before Ragnar. Horik challenges what has happened to their renewed agreement. Ragnar makes clear that he has never forgiven the attack on his family and announces that Borg will die by the blood eagle.