High on a grassy hill on the troubled island of Eirinn two young Druids eat the sacred bread of the Faerie folk and drink the holy Water of Life. With this wine and this bread Mawn and Sianan embrace the burden and the blessing of eternal life. They will be Wanderers through the endless years, sent as messengers to future generations to preserve the ancient customs and beliefs of the Druid king.
With the King and Queen of Munster, and their teacher, Gobann of the Silver Branch, they journey to Alba to help free the Gaels of Dal Araidhe from the savagery of the barbaric Saxons. Old friends, such as Declan, the Christian Abbot of Saint Ninian's, travel with them, as well as old enemies, such as Seginus Gallus, murderer, traitor, renegade priest.
The Saxons are not easily defeated, however. They have made a surprising alliance with a man hated and feared by the people of Eirinn, who brings with him techniques of war that heralds victory for the Saxons. A bloody battle is fought on Samhain day and what has been foretold for so many years finally comes to pass. Leaving the Wanderers alone on their endless cycle of the soul.