Final volume of the Celtic Crusades trilogy begun with The Iron Lance (1998), in which lawyer Gordon Murray was introduced as narrator of a Scottish generational saga, with Murdo Ranulfson, son of Lord Ranulf of Dyrness, Orkney, going off on the Crusades and finding the iron lance that stabbed Christ at the Crucifixion. In The Black Rood (2000), set 40 years later, Murdo’s son Duncan came back with a piece of the True Cross. Now, in this volume, a lass named Caitríonia seeks the Rosa Mysticus, or the Sacred Cup of the Christ at the Last Supper. This leads to Gordon himself becoming the cup’s guardian, century after century. No questions that would bother Graham Greene, but those lusting for the True Path will eat it up.