Full spoilers for this episode.
Lagertha's army meets Harald and Ivar's forces with Ragnar's sons divided between the camps. Before fighting, the leaders exchange hostages and try to find terms that might prevent their relatives from killing each other. Bjorn appeals to Ivar, and Lagertha argues against wasting their young men over land already belonging to them. Ivar briefly appears willing to give up his revenge, then reveals the offer as a taunt and renews his threat to kill her.
The battle opens on the field and in the nearby woods. Hvitserk takes men through the trees, where Lagertha's Sami allies attack them with darts. On the main battlefield, Harald calls for support, but Ivar holds back his reserve. Lagertha and Bjorn gain the advantage and force their opponents to retreat. Heahmund is badly wounded and left behind. Lagertha finds him still alive and orders that he be carried away rather than allowing him to die among the bodies.
Away from the battle, Alfred argues that Wessex needs a fleet to stop further invasions, while Aethelwulf remains occupied with military training. Iceland offers another dispute over what a community needs first. Floki wants a temple to Thor even while the settlers lack enough shelter, and Kjetill's offer to build it on his land sharpens Eyvind's suspicions. Lagertha wins this encounter, but the rival army survives to fight again.