The son of a man Arthur killed in battle seeks him out to learn how to fight, ostensibly to guard his people, in reality to take revenge. Part way through his training he realises Arthur is the man he wants to kill.
When Rolf, the preacher, arrives at a village, he causes trouble for Arthur because he preaches against war and fighting. Arthur is soon running out of warriors. The aggressive Mark of Cornwall is trying to solve the problem through force.
Arthur and Kai arrive at a village where the Saxons have attacked. All the men in the village have been enslaved and sent to the mines. Kai then takes Arthur and Llud prisoner to instigate a revolt in the slaves.
A Saxon ex-gladiator kidnaps two children of the wandering herbalist Wood People tribe, and will only return them in exchange for Arthur. It takes both Arthur's own warriors and the herbalists to save the day.
Arthur tricks Mark of Cornwall into travelling into Saxon territory with him and a small band of warriors, all disguised as Saxons, in order to retrieve a great treasure. But the treasure is not quite what Mark has been led to believe.
Morged, seething at being forced to ally with Arthur, demands Kai be handed over on a fake murder charge. Arthur refuses, demanding the right of single combat instead. Morged deputises Karn, the best swordsman in the land, to fight for him.
Kai discovers that the injured Saxon Mark of Cornwall is hunting is a childhood friend from before the death of his parents and the destruction of his village, and may be able to tell him who he really is.
The Greek trader demands 5 Saxon women as payment for the huge cask of good wine he delivers to Yorath. Rowena naturally objects. Can Arthur save the day without destroying his hard-won alliance with the Jutes?
Rowena, Yorath's feisty daughter, is determined to marry Mark of Cornwall, who only wants her for her land. Yorath strikes a deal with Arthur: he will stop Saxons sneaking into his territory if Arthur stops the marriage.
Saxon livestock is dying of pestilence: Amlodd the monk has the solution, but it requires the Celts and Saxons to work together. Cerdig is unhappy about the drastic action needed, and demands a hostage to ensure that Arthur keeps his word.
Kurk, an old friend of Llud's, is out to sell 3 prime cattle. Rowena wants to buy. However, on the way back to Yorath, Rowena and Llud are set on by the man who Kurk stole the cattle from originally. Then matters get complicated.
Eithna, daughter of Bavick, chief of his people and 'a Celt who kills Celts', is thrown by her horse on Arthur's lands and captured. Arthur seeks to use her as a ransom for Bavick to ally to him. Eithna has different ideas.
The haughty, high-born Roman, Benedicta, is shipwrecked and found wandering Arthur's lands. Rescued by Kai and Llud, she is reluctantly welcomed into Arthur's camp. Against their will, she and Arthur find themselves growing close.