|US Cover Artist:||Michael Heslop|
|UK Cover Artist:||Oliver Burston|
Will Stanton visits Wales to recover from hepatitis and meets Bran, the Pendragon and befriends him and his dog Cafall. Bran is an Albino with tawny eyes. His dog is totally white and has silvery eyes that can "see the wind". They seek the Golden Harp and awaken the Sleepers to fight the Dark. The Golden Harp was protected by the High Magic and three men: a Lord of the Dark, Artù, and Merriman Lyon. To find the harp they had to find a cave on Bird Rock during a fire. Upon entering the cave they had to be judged by the High Magic to deem them worthy of retrieving the Golden Harp. The three men give Bran and Will riddles that they solve and eventually get the harp. When they find the Harp, a crabby old farmer named Caradog Prichard kills Cafall, thinking that the dog killed one of his sheep, when it really was the milgwn. Bran and Will go to the lake where the Sleepers sleep. At the end of the book, Caradog Prichard was possessed by the Grey King and tried to battle Will but Will played the harp. Then, Caradog Prichard put the Harp in the lake. In this book, the main protagonist is Will Stanton.
The Grey King was awarded the 1976 Newberry Medal.
Welsh folklore is an important point in the book.