Ragnar fights Jarl Borg to win back Kattegat.
Tropes:
- But Now I Must Go: Lagertha leaves Kattegat to return to her husband.
- Foe-Tossing Charge: Jarl Borg's army stops to run over Ragnar's forces, knocking several of them aside.
- Human Sacrifice: Ragnar orders Bjorn to behead one of Jarl Borg's men as a sacrifice for Odin.
- I Choose to Stay: Bjorn wants to remain in Kattegat with his father. Lagertha eventually allows it, with a heavy heart.
- Man Hug: Bjorn and Rollo hug each other upon meeting again.
- Offscreen Moment of Awesome: King Ecbert single-handedly annihilates King Horik's troops, causing him to flee from Wessex in a period of weeks.
- Parent-Child Team: For the first time, Ragnar and Bjorn battle side by side, as Bjorn always wanted since he was a child. First, they burn Jarl Borg's food supplies during an attack at night, then Bjorn joins Ragnar's army in the battle against Borg.
- Rightful King Returns: When Ragnar and his people return to Kattegat after defeating Jarl Borg, the people there receive them with great enthusiasm and relief.
- Shield Bash: In the battle, Rollo loses his axe and fights only with his shield for a while before he finds a new one.
