Persecuted and hunted by Christianizing forces, young Deirdre and her clan eke out an itinerant existence in the forest. When the threat grows more imminent, Deidre's mother, Brigid, is led by a ritualistic vision to make a transformative choice: she offers herself as holy sacrifice. Many years later, Deirdre and her father, Orson, are all that remain of the clan. Deirdre and Orson embark upon a harrowing and hallucinatory journey to find Brigid, one that will lead them across the threshold of death and far beyond.