The protagonists of the story are Mordred and his father the king, Arthur. Lost as a youth, Mordred is raised by fisherfolk until he is returned to his birth mother Morgause. The novel portrays Mordred as a pawn of fate unlike many tales which paint him as the villain of the Arthurian saga.
The novel covers the time after Merlin's self-imposed exile and stretches to the deaths of Mordred and Arthur.