Tensions escalate between two clans, threatening their fragile peace. On one side stand the Túath, on the other the Milidh. The prize: control of the land of Éire. Yet amidst this brewing conflict, another more dangerous threat looms. The village of Tara is ripped apart, not by war, but by the seed of betrayal as the priestess' own kinswoman, Gráinne, conspires to seize control. Enemies shall become allies and Shiovra is faced with a difficult choice, one that will ultimately engulf her world in an irreversible eclipse.