Shadow of Stone by Ruth Nestvold

For over ten years, there has been peace in Britain after Arthur and his warriors soundly defeated the Saxons at the battle of Caer Baddon. But sometimes peace is deceptive ...

After a series of hard winters and famine, an alliance of dissatisfied northern kings attack the rich cities of Southern Britain. But in the years of peace, Arthur's army has grown soft; jealousies and trivialities rip once strong alliances apart. Cador, who is mockingly referred to as "farmer king," must go to war again. The threat to their way of life throws him together with Yseult, the woman he has secretly loved since he was a youth.

But can their politically expedient marriage help bring peace to Britain again? Or will it only lead to further conflict? As betrayals both real and imagined shake the foundations of former British unity, Cador and Yseult must try to negotiate their own personal peace. Who will survive the upheavals to come? Will Britain rally once more behind a common leader to fight off the common threat?

Shadow of Stone:
There was once a woman, fair as the moon, who lived most of her life beyond the realm of legend. As she stood beside the grave of her lover, the legend that ended with his death was far from her mind. Her soul felt as dark as the shadow cast by Drystan's standing stone, dark and barren. Love was over, but life was not; she would have to find a way to go on, for the sake of their son.

This is the story of how Yseult outlived the legend that had been her life.

Praise for Ruth Nestvold:
"... an excellent up-and-comer."
- Cory Doctorow at Boing Boing