The siege of Jomsborg fortress drags on. Thorkell's army, camped outside the fortress, and Floki's army, protected by the city's impregnable ramparts, continue their war of succession in the name of their champions, Thorfinn and Baldur, without caring that neither of them has the slightest desire to become the Supreme Commander of the Jomsvikings. At Floki's order, Gudrid is held hostage inside the fortress.
Floki hopes to use her to lure Thorfinn into an ambush and kill him. He is unaware that Baldur has revealed to Einar the existence of a secret passage connecting the Jomsborg well to the river, on the other side of the ramparts, in the hope that he will negotiate peace with Thorfinn and Thorkell...