In this latest of Gordon R. Dickson's immensely popular adventures of Jim Eckert; the 20th-century mathematician who has come to live in a medieval age where magic works and Jim himself can become a dragon at will, Gordon R. Dickson draws on the richness of the greatest medieval legend of all, the tale of Arthur and his Knights of the Round Table.In the legends, after their final battle, Arthur and his knights went to Lyonesse, the land under the sea. Now Lyonesse is threatened by a resurgence of the Dark Powers, those mindlessly malevolent forces that struggle to stop the course of History. And Jim Eckert and his friends are called upon to stop them.Arthur and his court live on in Lyonesse because, even though centuries have elapsed, there are still those who believe in them. But Arthur and his knights are proud, too proud to easily accept help from Jim Eckert and his allies. But they will have help, from Jim in his dragon form, from knight-in-armor Sir Brian Neville-Smyth, from the brilliant archer Dafydd ap Hywel, and from one small hobgoblin. The result is a wild ride, an Arthurian fantasy adventure as only Gordon R. Dickson could tell it.