Since the sudden death of the Supreme Commander of the Jomsvikings, two factions are clashing for control of Jomsborg. Floki's faction, which wants the title for his grandson Baldur, who is still a child, and Vagn's faction, which has chosen Thorfinn, son of Thor, as its leader without asking his opinion.
Ready to do anything to get rid of Thorfinn, Floki sent his best assassin, Garm, to kill him. But instead, he returns with Vagn's head and three hostages: Leif, Einar, and Gudrid.
The murder of Vagn provokes Thorkell's anger, who breaks his alliance with Floki and marches with his army on Jomsborg.