London, 1019: a few months have passed since Thorgils has escaped the clutches of the Irish Church only to find himself at the centre of a capricious love affair with Aelfgifu, wife of Knut the Great, ruler of England, and one of the most powerful men of the Viking empire. A passionate relationship between two unlikely lovers begins to unfold, which forebodes uncontrollable consequences... When Thorgils is finally on the run again, he meets Grettir, an outlaw who is feared by most for his volatile and brooding behaviour. The two men become travel companions and sworn brothers - which binds them together beyond death. At the gates of Byzantium Thorgils' loyalty is put to the ultimate test... Sworn Brother continues an utterly compelling journey back in time to a world that is brimming with wonderfully crafted characters and their insatiable hunger for riches and renown.