Waymakers (Champions of the Crystal Book 9)

Five years after the Kyan invasion of Praxatillus nearly succeeded, there is an uneasy feeling in the Realm that the worst of the war lies ahead. With the Guardian and combined Wayship/Praxatillus fleet still missing, Sabrina Devon has been trying to train the Inheritor to defend them all in her mother's absence. But when a massive Kyan troop ship appears in orbit without warning, it seems they have run out of time....