Daughters of Fire and Sea - Daughters of Fire and Sea, #1

Born of fire and sea, twin sisters begin a perilous journey that will either save the world or destroy it. Since the disappearance of their mother, Elaina, four years ago, twin sisters Lyric and Runa Graymorn have been living on their own. They've always known there were secrets in their past, but when Elaina's shocking return threatens their lives, the sisters must flee from the only home they've ever known.
Traveling far from their small village, Lyric and Runa learn that myths are more real than they imagined, and there is magic in their blood, magic they can use. But their unexpected adventure brings new dangers, and the choices they make will affect the future of their world.