At a time when ancient Celtic beliefs are retreating before the rise of Christianity, the goddess Ahès seeks to preserve the power of the old gods. She brings about the birth of Merlin, a child destined to become an instrument in this struggle and oppose the new religious order. As he grows, however, Merlin discovers his own powers, the peoples and creatures shaping Britain, and the conflicting ambitions of those who wish to guide his destiny. Among druids, deities, dragons, and figures from Arthurian legend, his journey gradually leads him toward the events that will eventually bring about the rise of King Arthur.