In the kingdom of Dumnonia, King Cador has lost his knowledge of the old magic, which now calls instead to his three children: Riva, the healer who cannot heal herself; Keyne, who battles to be accepted as the king's son; and Sinne, who dreams of finding adventure. As they fight against the invading Saxons, they must also contend with the meddlesome magician Myrdhin, and Tristan, a warrior who is not what he seems. Riva, Keyne, and Sinne are soon entangled in a web of betrayal, and their actions will shape the destiny of Britain.