Unforgiven - Lauren Kate

High school can be hell. Cam knows what it's like to be haunted. He's spent more time in Hell than any angel ever should. And his freshest Hell is high school, where Lilith, the girl he can't stop loving, is serving out a punishment for his crimes. Cam made a bet with Lucifer: he has fifteen days to convince the only girl who really matters to him to love him again. If he succeeds, Lilith will be allowed back into the world, and they can live their lives together. But if he fails ...there's a special place in Hell just for him. Tick-tock. The long-awaited new novel in the global bestselling Fallen series.