In AD 873, war and overcrowding in Norway prompts Eivor and their adoptive older brother Sigurd to lead their clan of Vikings to settle new lands in Anglo-Saxon England, as part of the Viking expansion across Europe. The clan comes into conflict with the kingdoms of Wessex, Northumbria, East Anglia, and Mercia over the next several years,as well as the warring sons of the legendary Viking warrior Ragnar Lothbrok, who made up the Great Heathen Army.Eivor's clan faces forces led by the leaders of these kingdoms, including Alfred the Great, the king of Wessex.It is during this time that Eivor meets the Hidden Ones and joins their fight against the Order of the Ancients. Explorable cities include Winchester, London, and York. Parts of Norway and Vinlandare also included,while dreamscapes of Asgardand Jotunheim also feature.
As with previous games in the series, Valhallafeatures a narrative set in the modern day. This story follows Layla Hassan, the modern-day protagonist previously featured in Origins and Odyssey. Valhallaalso contains story elements related to the Isu, who, as part of the lore of the Assassin's Creed series, are an advanced civilisation that pre-date humanity.