The Hiraeth trilogy darkens. After their victorious battle in Wicklow, Mona disappears without a trace. Despite months of searching, Cai is forced to face life without her, and seeks happiness in a life far removed from his Welsh language and community. Mona's dramatic return throws his life into chaos, as she reveals the harrowing details of the past fifteen months at the hands of their true enemy. With the Welsh and Irish Druids uniting behind them, Mona and Cai must stand together, if they are to overcome the powerful and evil force, to which their own destinies are fatally entwined.