Ivar and Hvitserk are ready for battle to avenge their mother. Ivar asks Hvitserk if he's ready to kill Ubbe and Hvitserk makes a joke out of it. Astrid tells Harald that she's going with him even though she's with child. Ivar gives Heahmund his sword back. Bjorn is happy to be taking Guthrum with him to battle. Torvi watches as Bjorn says goodbye to Snaefrid. Torvi gives her children to Margrethe to look after while she goes into battle. Bjorn and Lagertha lead the train as they head off to battle. Floki watches from above as the settlers build a settlement. Floki suggests that they build a temple for Thor but some think that they should build their own homes first. One, in particular, is very vocal about his disappointment in this place. Lagertha meets Ivar's forces. Lagertha says that it isn't right that the sons of Ragnar try to slaughter each other. Lagertha says that they will send emissaries and Bjorn agrees.
Bjorn and Halfdan go forth to talk to Hvitserk and Harald. They exchange hostages and decide to meet again tomorrow about the alternatives to fighting. Ubbe asks Hvitserk if he regrets siding with Ivar and Hvitserk says no. Ubbe asks about Heahmund and Hvitserk tells them that he is a great warrior. Lagertha asks Hvitserk to help them avoid endless slaughter. Halfdan tells Harald that this is madness. Harald tells Halfdan that he doesn't want to have to fight against him. Ivar tells Halfdan that he has to choose between a friend or his brother. Ubbe tells Hvitserk that he doesn't want to have to kill him in battle. At the peace summit, Bjorn asks them to put aside their differences for the sake of their father. Ubbe asks Ivar to forgive him then they can make an accord. Lagertha says that they should be discussing how to combine their armies and have them out searching for new land. She tries to beseech Astrid but Astrid tells her that she is married now to Harald.
Ubbe begs Ivar not to proceed with the war because they are sons of Ragna. Ivar decides that there will be no battles. Harald asks him what is this and Ivar says that he can't go up against his brothers. That he still feels guilty for killing Sigurd. They join around and have a drink to seal the accord but Ivar throws his drink in Ubbe's face. He tells them that he can't break his promise and that he will kill Lagertha. He tells Ubbe that he is no longer his brother. They separate into two groups but Lagertha says that they won't fight right now. Halfdan tells Harald that Bjorn saved his life and Harald backhands him and tells Halfdan that he will kill him. Alfred and Judith watch as Aethelwulf and Aethelred practice fighting down in the courtyard. Alfred tells Judith that they need to build a navy to prevent the Vikings from future attacks. Judith tells Alfred to talk to Aethelwulf about it but Alfred says that Aethelwulf is too set in his ways.
Floki sits aside while the settlers begin to build houses. Heahmund says that he is here to do gods will but Ivar reminds him that he'll be doing Ivar's as well. Ivar says that he's going to pull back a third of their army just in case Bjorn is up to something. Harald agrees and tells Astrid to go back with Ivar. The two armies fight each other. Hvitserk takes a portion of the army into the woods but they are ambushed by the Sami. They can hear the fighting and Astrid says that they should leave but Ivar tells her to wait. Harald sounds the horn and Astrid says that they need them. Ivar says that it's too late. Realizing that they're outnumbered, Harald sounds the retreat. Harald meets up with Ivar and tells him that Heahmund is dead. Lagertha walks through the field and finds that Heahmund is still alive. Lagertha asks Bjorn to save him.
- Katheryn Winnick as Queen Lagertha
- Gustaf Skarsgård as Floki
- Alexander Ludwig as Bjorn
- Peter Franzén as King Harald 'Finehair'
- Jasper Pääkkönen as Halfdan the Black
- Moe Dunford as Aethelwulf
- Alex Høgh as Ivar the Boneless
- Marco Ilsø as Hvitserk
- Jordan Patrick Smith as Ubbe
- Jonathan Rhys Meyers as Bishop Heahmund
- Josefin Asplund as Astrid
- Adam Copeland as Ketjill "Flatnose"
- Kris Holden-Reid as Eyvind
- Ida Marie Nielsen as Margrethe
- Ferdia Walsh-Peelo as Alfred the Great
- Georgia Hirst as Torvi
- Jennie Jacques as Queen Judith
Additional cast (in order of appearance)
- Ben Roe as Guthrum
- Ryan Henson as Hali
- Svea Killoran as Asa
- Anthony Brophy as King Svase
- Dagny Backer Johnson as Snaefrid
- Leah McNamara as Aud
- Jack McEvoy as Helgi the Lean
- Mei Bignall as Thorunn
- Kelly Campbell as Ingvild
- James Craze as Bul
- Elijah Rowen as Asbjorn
- Donna Dent as Rafarta
- Scott Graham as Frodi
- Lulubelle Earley as Jorunn
- Darren Cahill as Aethelred