Ariel is a seventeen-year-old girl whose life takes a completely different turn on the day she comes late to school. There's a new, very handsome, dark-haired boy, Devin, in her class, but to Ariel's surprise everyone seems to know him, and her best friend claims he's been going with them to school for years, except Ariel is sure she has never seen him before. Convinced her friends are messing with her, Ariel pretends nothing weird is going on. She even considers the possibility of having a brain disease ... until she starts having visions of unknown people with wings and unusual eyes. What's worse, her visions hint that Devin might be a demon who came to the human world to take an angel to Hell. As she becomes more and more aware of the existence of angels and demons, Ariel finds out her sister is the angel that the demons want to take. Determined not to let anyone harm her sister, she will do anything, even try to kill the demon on her own. But can she really kill Devin when he appears so human, and what will she do when she reveals the secrets surrounding her true nature? Because, let's face it, a girl who can see both demons and angels in her visions can't really be human.