Astrid tells Harald she's coming with them, pregnant or not. He relents and allows her to sail with them.
Both sides prepare for war. Bjorn takes his oldest son to his first battle.
Floki's people continue to argue over their new settlement.
Bjorn and Harald agree to talk through other options before fighting. They exchange hostages (Halfdan and Hvitserk) in the mean time.
Harald and Ivar try to convince Halfdan to switch sides. Ubbe tries to do the same with Hvitserk.
Lagertha's side pleads for peace. Harald still wants to fight, so the decision comes down to Ivar. Ivar decides he does not want to fight his brothers. He immediately changes his mind though and tells them to surrender Kattegat.
Floki's people begin building their settlement.
Ivar wants to split their army to defend their ships and have Hvitserk go into the woods to try to divide Bjorn's forces. Harald insists Astrid go with Ivar despite her wishes to stay and fight.
The battle begins with Bjorn, Hvitserk, and Ivar all split up. Hvitserk finds his men surrounded and pulls back. Harald soon finds his men surrounded as well as Lagertha leads another group from behind.
Ivar stops to wait to see if he was right before continuing on to the ships. Ivar and Astrid hear the horn calling them back to the battle. Astrid wants to go back, but Ivar says it's too late.
Bishop Heahmund is struck down.
Harald's army retreats in defeat.
Lagertha finds Heahmund and discovers he's alive. She wants to save him.