After the legendary Battle of Athendun, King Alfred and Wessex basks in the glory of victory. But King Alfred knows the Danes are not fully defeated. He turns his attentions north towards the city of Eoferwic (York), where the people are ruled mercilessly by two war-hungry Dane brothers named Erik and Sigefried. The brothers depart from Eoferwic to battle the Scots, leaving a commander named Haesten in charge of the city. But the Christian priests who lived there under subjugation seize the opportunity of Erik and Sigefried's absence to revolt and kill all the Danes. Not long after this, Uhtred, accompanied by Hilde and Halig, come upon the city. Uhtred has begun his journey back north, but spends his nights drinking and whoring. Hilde does her best to remind him why it is they go north: to free Uhtred's enslaved sister from Kjartan, the same man who killed his Viking father.
In the city square, the Saxons have tied Haesten, the only surviving Dane, to ropes and make him fight various members of the crowd for amusement. Uhtred frees him to the anger of the townsfolk, but is pardoned when they learn his name, which has already reached legendary status following the Battle of Athendun.
There Uhtred coincidentally reunites with Father Beocca, who has left Winchester on Alfred's orders with Brother Trew to free an enslaved northman prophesied to be the next King of Northumbria. According to Brother Trew, Father Eadred of Cumberland claimed Saint Cuthbert came to him in a vision, and spoke of this Guthred who would be king. The two priests have taken silver from the church, granted by Alfred, to pay the ransom fee for Guthred's freedom. Beocca tries to recruit Uhtred to his cause, knowing a skilled warrior would help them their task. But Uhtred wasn't convinced in joining until he heard that Guthred's father was killed by the one and only Kjartan, and is now enslaved on his lands. He now sees an opportunity to attack Kjartan if this future king and potential future army were on his side.
To free him, Uhtred devises a plot using the three lepers traveling with Beocca. Using the skull of a dead animal, he masks himself as an undead horsemen (four apocalyptic horsemen total) sent to take the souls of Kjartan and Kjartansson. They attack the slave trade auction at night and everything goes to plan. All the people in attendance fear Uhtred's Undead Horseman figure and flee. Uhtred knocks out one-eyed Sven, blindfolds and ties him, and releases him to find his way back home. Kjartan is enraged that he was bested by a make-believe figure, and gets angrier when the dogs in the cellar won't stop barking. He yells at Sven to "shut his bitch up". Sven descends into the cellar to tell Thyra (Ragnar's kidnapped daughter) to make the hounds be quiet. He is clearly afraid of her.
Meanwhile, Guthred feels indebted to Uhtred and offers to make him the commander of his army. Uhtred, knowing he would need an army to command if he were to overtake Dunham where Kjartan lives, accepts. They travel to Cumberland where the village folk greet the new king warmly. Guthred is sworn in over the bones of Saint Cuthbert as the new King of Cumberland.