Casimir, the relentlessly scheming king of Lyonesse, has learned the child he thought was his grandaughter, Madouc, is in fact a fairy changeling. This is somehow wrapped up in the mystery of Dhrun, son of King Ailias of Troicenet, of whom it was prophecied by a magic mirror that he would be the king of all the Elder Isles. Not if Casimir can help it. He wants that throne for himself. And there are much larger, darker schemes afoot, as the evil magician Tamurello and the mysterious witch Desmei plot against Murgen, the Elder Isle's greatest wizard, who alone keeps the Elder Isles from sinking into the sea. And into this web of political and magical intrigue wanders Madouc, determined to learn her pedigree, possessed of a bit of her fairy mother's magic and a truly wonderful charm all her own.