The Coranians have won the war, and Kymru is defeated. For Havgan, however, the victory is not complete. Cadair Idris, the hall of the High Kings, remains closed to him. To gain entrance, he must locate the Four Treasures—the Stone, the Spear, the Cauldron, and the Sword—and bring them to the Guardian of the Doors. Only then can he proclaim himself High King of Kymru. But the Treasures were hidden long ago. In order to save Kymru, Gwydion the Dreamer must locate a long-forgotten song and the clues it contains before Havgan does. Following the dictates of the song, he persuades Rhiannon, her daughter Gwenhwyvar, and his nephew Arthur to set out with him on the dangerous quest. Dogged by Havgan's soldiers, they must hurry to find the artifacts. Soon, distrust and fear complicate their already difficult journey, and one of them must risk life and limb on the next move in their deadly game.