Patricia A. McKillip

She saw the knight in the mirror at sunset… During the wedding festivities of his king, Cyan Dag, a knight of Gloinmere, is sought out by a mysterious bard and told a terrifying tale: that the king has married a false queen—a lie cloaked in ancient and powerful sorcery. Spurred on by his steadfast honor and loyalty, Cyan departs on a dangerous quest to rescue the real queen from her tower prison, to prevent war, and to awaken magic in a land that has lost its way…