On the night of Guinevere's birth, a wise woman declares a prophecy of doom for the child: She will be gwenhwyfar, the white shadow, destined to betray her king, and be herself betrayed. Years pass, and Guinevere becomes a great beauty, riding free across Northern Wales on her beloved horse. She is entranced by the tales of the valorous Arthur, a courageous warrior who seems to Guinevere no mere man, but a legend. Then she finds herself betrothed to him and, like the knights that follow him, swiftly falls under Arthur's spell . . .At the side of King Arthur, Guinevere reigns strong and true. Yet she soon learns how the dark prophecy will reveal itself - she is unable to conceive. Arthur's only true heir is Mordred, offspring of a cursed encounter with the witch Morgause. Now Guinevere makes a fateful choice: To raise the child as her own to teach him to be a ruler and to honour Camelot. Mordred will be her greatest joy - and the key to her ultimate downfall.