Traitor's Moon: The Nightrunner Series, Book 3

Seregil and Alec have spent the last two years in self-imposed exile, far from their adopted homeland, Skala, and the bitter memories there. But their time of peace is shattered by a desperate summons from Queen Idrilain, asking them to aid her daughter on a mission to Aurenen, the very land from which Seregil was exiled in his youth.