While bathing in a stream in the middle of winter, Uhtred is confronted by Odda the Younger, who bribes him to walk away from the arranged marriage Alfred has planned for him. The girl is Mildreth, goddaughter of Odda the Elder, and someone that Young Odda seems to harbor secret feelings for and would hate to see betrothed to a Dane. Uhtred has already paid the bride price of 33 pieces of silver and though Leofric states that she is "plain", Uhtred knows that she owns land and will therefore serve his long-term purpose of giving him what he needs to be a respected Ealdorman. In the chapel, Mildreth removes her hood and Uhtred sees her for the first time with a look of pleasant surprise on his face.
Uhtred, Mildreth, and Leofric set out to their new home as the winter starts to thaw. Uhtred, a little disbelieving that Alfred would gift him such a beautiful bride, begins to ask prodding questions and soon learns that Mildreth's deceased father had promised a tenth of his land's yield to the Church, despite not being able to pay in full for many years. The sum of the current debt is 2,000 shillings, which Alfred could remove but has chosen not to in order to test Uhtred's obedience as an English Ealdorman.
Upon arrival in Lyscombe, Mildreth greets her commonfolk and gifts them the silver from her bride price, of which Uhtred learns she was cheated by almost half. Their first night as a couple is tense as Uhtred's quick temper clashes with Mildreth's meek nature.
Months pass and Mildreth is now pregnant. She joins Uhtred and Oswald on an overlooking ridge as they patrol their lands, seeing an endless line of Danes crossing through the trees, amongst whom is Young Ragnar. Uhtred rides with Mildreth and Leofric at once to Winchester to warn Alfred. The peace has been broken and King Guthrum's army marches west towards Wareham. In retaliation, a great Wessex army is raised and sets out to meet them.
Uhtred takes an opportunity at base camp to confront Alfred about the outstanding debt of his deviously arranged marriage. But before Uhtred can begin, Alfred informs him that Ivar the Boneless, brother of Ubba, has been killed in Ireland and Ubba has deserted Guthrum to avenge him. The discussion leads to an argument about the gods versus the one true God. Which god, or gods, provides omens or miracles? Do they not have the same effect? Alfred reveals that his distrust of the Danes (and therefore Uhtred) stems from their desire for personal gain and pleasure without sacrifice. To Alfred, penance is what separates the good English Christians from the pagan heathens. As a vegetarian, Alfred has his broth. As an Ealdorman, Uhtred has his debt. It is how Uhtred acts in the face of this dilemma that will determine Alfred's trust in him.
Wareham has fallen at the hands of the Danes. Ragnar, eager to lead his men against the Saxon army and continue westward conquest, interrupts Guthrum's moment of reverence inside the Christian church, which he finds "strangely quiet and peaceful". But Guthrum fears losing more men in the wake of Ubba's desertion and admits that despite overtaking Wareham, they can be starved out. In talks at the gate, Alfred demands the Danes exit Wessex by ship back to East Anglia in one month's time. Ten hostages from each side are exchanged as a condition during the one month peace term. Among the Wessex hostages are Father Selbix, who has been instructed to convert Guthrum to Christianity, and Uhtred, who has been instructed to escape and light beacon signals should word of Ubba's return be heard.
That night in Wareham, the reunion between Uhtred, Ragnar, and Brida is joyful as they drink together. Uhtred finally feels at home, but his new Saxon family proves to be another obstacle in his Danish affinity. Albeit tempted to join Ragnar, he is still drawn towards the dream of Bebbanburg despite Alfred's incessant attempts to test his allegiance. He continues to grapple with his two identities, never fully accepted by either side.
A messenger arrives from Ireland with the news of Ubba's return to England as well as reinforcements from London. This is all the news Guthrum needs to hear to know he can defeat Alfred in battle and orders his men to get rid of the English hostages. All but Uhtred is slain when Ragnar steps in and tells Guthrum that he will have to kill him first if he wants to kill Uhtred.
Uhtred is released and lights the signal beacons as Alfred instructed, once again demonstrating that he sides with the Saxons.