Vanguard by Ann Aguirre

The Razorland saga continues. Since the war ended, Tegan has dreamed of an epic journey, so when she has the opportunity to sign on as ship’s doctor, she can’t wait. It’s past time to chart her course. Millie Faraday, the kindest girl in the free territories, also yearns to outrun her reputation, and warrior-poet James Morrow would follow Tegan to the ends of the earth.

Their company seems set, but fate brings one more to their number. Tegan will battle incredible odds while aiding Szarok, the Uroch vanguard, who has ventured forth to save his people. Szarok is strange and beautiful, like a flower that blooms only in the dark. She shouldn’t allow him close, as such a relationship is both alien and forbidden. But through stormy seas and strange lands, she will become stronger than she ever knew.