The Celts believed in benign spirits and demonic forces, but made no churches or temples: nature itself was their cathedral. Kenneally visits ancient Celtic settlements in Austria, Italy and Greece. He explores the settlement of Castell Henllys in Wales, where the religion of the druids was broken by Roman military might. And at Newgrange, Ferrycarraig and Dun Aengus in Ireland, he reveals how the Celts came to adopt the Gods of those who had preceded them.