The angels fell in heaps of blood and broken bones. Cassie Larke watched, like all humans, as they died on the streets and the world grew dark and cold. 

Twelve years later, Cassie discovered a strange man adrift at sea, with no memory of who he was or where he came from. When no one else can see him, Cassie begins to wonder if he's an angel.

People are dying, and someone or something is after Cassie and her wayward angel. Does she have what it takes to save them both?