The Dark Star (The Callenlas Chronicles #1)

In Callenlas, dragons carry riders on adventures, and stars are rumoured to live among human beings. Caught up in a war that threatens everything they have ever known, a downtrodden apprentice and a discontented princess find themselves drawn closer and closer to the great King Elior. Will he prove to be Zaphreth's greatest enemy, or the hero of Runa's legends?