Curse of Shadows and Light — Penelope King

Book #3 in the bestselling Demonblood Series. "For one to live, the other must die." Devastated. Exiled. Hunted. Lucky and Liora's life has never been easy. But up until now at least they had a home...at least they had him. But all that is gone and it's time to start over in a new place. A place with new friends, and new enemies, and new dangers. Only now, it's coming from both sides. Angels and demons want them dead. Because only Lucky and Liora hold the key that can tip the balance of power, and undo everything. Unless one of them makes the ultimate sacrifice. The question is...who?