The Outcast Chronicles, book 3: Sanctuary
Rowena Cory Daniells2012

For over three hundred years, the mystics lived alongside the true-men, until King Charald laid siege to the mystic’s island city and exiled them. Imoshen, most powerful of the female mystics, was elected to lead her people into exile. She faces threats from within, from male mystics who think they would make a better leader. And her people face threats from true-men, who have confiscated their ships. They must set sail by the first day of winter. Those who are left behind will be executed.

Once they set sail, they face winter storms, hostile harbours and sea-raiders who know their ships are laden with treasure. Imoshen relies on the sea captain, ardonyx, for advice, and Sorne, the half-blood mystic, who has lived among the true-men kingdoms of the Secluded Sea. But Imoshen knows the mystics can’t run for ever. They need somewhere to call home. They need... Sanctuary.