The fourth season picks up years after the death of King Alfred, with England's dream of unification more fractured than ever.
Following the death of Lord Æthelred, a power vacuum triggers political turmoil. King Edward and Lady Æthelflæd compete for control while the Danes, led by Cnut and later Sigtryggr, launch new invasions.
Uhtred attempts to reclaim his ancestral home of Bebbanburg after hearing its defenses are weakened by Scottish attacks. However, the return of his cousin Wihtgar leads to a tragic failure and the loss of a dear friend.