With the old magic fading and the ways of humankind banishing the Old Ones, Ireland is threatened with the loss of its mystical roots, and it is up to Fianne, the daughter of Niamh, to solve the riddles of power.
The young seer Sibeal is visiting an island of elite warriors, prior to making her final pledge as a druid, when she finds Felix, a survivor of a Viking shipwreck, who's lost his memory.
After escaping her wrongful imprisonment, magical healer Blackthorn, living on the fringe of a mysterious forest with a former prison mate named Grim, is duty bound to assist anyone who asks for her help.