The first episode investigates how the ferocious Viking forces prepared for invasion in Denmark before launching their terrifying attack on England. Dr Xand van Tulleken and Raksha Dave explore the bitter feud between the weak King Ethelred and his treacherous son Edmund, and the progress of the Vikings' bloody onslaught as its armies arrive in England and begin their savage attack, first on the south coast.

Xand visits an ancient Danish fort and experiences Viking battle training first hand. He then finds out what life was like for a Viking warrior on board their cutting-edge longships. In Cambridge, Raksha learns how the Vikings raped and pillaged the land, extorting millions in today's money through fear and brutality. Via modern scientific research she investigates one of the most bloody and legendary means of Viking retribution.

Dr Xand Van Tulleken and archaeologist Raksha Dave follow the story of the Viking invaders as they prepare for one final showdown for the crown of England. The two young would-be kings, Edmund Ironside and Canute, are ready to fight to the death to take the English throne. Alliances are broken then re-made, and then an act of betrayal amid a terrifying battle transforms the course of history.