Mercy O'Connor is becoming an angel. She can feel her wings sprouting from her shoulder blades. They itch. Sometimes she even hears them rustling. And angels don't need to eat. So Mercy has decided she doesn't need to either. She is not sick, doesn't suffer from anorexia, is not trying to kill herself. She is an angel, and angels simply don't need food. When her parents send her to an eating disorder clinic, Mercy is scared and confused. She isn't like the other girls who are so obviously sick. If people could just see her wings, they would know. But her wings don't come and Mercy begins to have doubts. What if she isn't really an angel? What if she's just a girl? What if she is killing herself? Can she stop?