Uhtred is given a task from Alfred to build one fortified town, after capturing some raiders, Uhtred discovers that there are two Norse earls, Sigefrid and Erik Thurgilson in the region, and these two are allied with Uhtred’s former friend Haesten, that once has sworn to serve Uhtred. The invaders are settled near to Lundene (London), Uhtred informs Alfred, and Alfred demands Uhtred to take the city back, and hand over it to his cousin Æthelred.

Haesten invites Uhtred to a meeting near the Thames river in Mercia, Haesten takes Uhtred to a graveyard, where a man raising from the dead is telling some prophecies, and this man says to Uhtred that he is to be King of Mercia. Tempted by the prophecy, and summing it up with his dislike for Alfred and his Christian beliefs, Uhtred decides to listen to Haesten and Thurgilson’s proposition: to convince Ragnar to ally with them, and together they would conquer East Anglia, Mercia, and finally Wessex, in this way Uhtred would receive Mercia, Sigefrid Wessex, and Haesten East Anglia.

Uhtred was still thinking about the proposition, and in the meantime, Sigefrid invites him to watch the crucifixion of some prisoners, between them Uhtred recognizes an old friend and experienced fighter, the Welshman Father Pyrlig. Uhtred convinces Siegfried to accept single combat against Pyrlig, Pyrlig wins the fight and all prisoners are freed. Pyrlig then tells Uhtred that the man rising from the dead is a trick, a living man put into a grave but with a duct to breathe through, Uhtred swears to Pyrlig to keep his oath to Alfred.

King Alfred has the intention to unite the Kingdoms and takes one step giving his older daughter, Æthelflaed in marriage to Æthelred, bonding Mercia to Wessex. Also, Alfred sees Lundene as an important area and he wants to recapture it, Æthelred then is put in command of the warriors, and Uhtred goes with them as an advisor. Æthelred changes Uhtred’s plans, but this was not the real plan, Uhtred’s real plan is to invade by boat taking a risky path to enter the city. The defenders' sally to attack Æthelred’s men, but this put them in between Æthelred’s and Uhtred’s men. Osferth, a bastard son of Alfred, strikes Sigefrid and cripples him. The Norseman is defeated, and Uhtred allows them to retreat to avoid losing more of his men. The Norses retreat to Beamfleot where Haesten is based, and Alfred puts Uhtred in charge of the military of Lundene.

Uhtred is very fond of Æthelflaed, and this makes Æthelred furious, the relationship between Uhtred and Æthelred was never good, also not good with Æthelred’s advisor Aldhelm, and it gets even worse after Æthelred starts to beat Æthelflaed. A strong Danish fleet led by Gunnkel Rodeson attacks one of Alfred’s burhs, Alfred uses his strong force to repel the attack, however, Æthelred doesn’t move his forces to trap the enemy as planned, and this gives them a chance to flee and some to join Sigefrid.

Alfred finally notices the lack of action of Æthelred, and orders him to attack Gunnkel, however, after an initial success everything goes wrong and he is forced to retreat, and also loses his wife that is captured. Uhtred is then sent to negotiate with Sigefrid, and he discovers that Erik and Æthelflaed have fallen in love, and they are even planning to flee together.

Uhtred takes a ship with his closest men to help Erik and Æthelflaed to escape, he needs to remove a ship that is blocking the passage to the sea, but when he arrives he discovers Sigefrid halls in flames; Haesten has betrayed Sigefrid and kidnapped Æthelflaed, looking to get the ransom for himself. Uhtred now needs to keep the blockage to prevent Haesten from escaping. A big fights starts, where Sigefrid recaptures Æthelflaed and Haesten flees, but when Erik tries to get Æthelflaed back he is blocked by his brother Sigefrid that now has figured out their plans, they fight and Erick ended being killed by Sigefrid.

Uhtred and his men attack Sigefrid, quickly defeating them, and Uhtred gives Osferth an order to kill Sigefrid. Now that Erik is dead Uhtred has no other choice than bringing Æthelflaed back to Mercia.