Vespertine

"Vespertine" is a breathtaking YA fantasy about a young Gray Sister named Artemisia, who must defend her world against restless spirits of the dead. When her convent is attacked by possessed soldiers, Artemisia awakens an ancient spirit bound to a saint's relic, but wielding its extraordinary power almost consumes her. Facing a sinister mystery of saints, secrets, and dark magic, Artemisia turns to the last remaining expert for help: the revenant itself. But as their bond grows, she realizes that facing this enemy might require her to betray everything she's been taught to believe.