The Star Child — Stephanie Keyes

The world is about to be cloaked in darkness. Only one can stop the night. Kellen St. James has spent his entire life being overlooked as an unwanted, ordinary, slightly geeky kid. That is until a beautiful girl, one who has haunted his dreams for the past eleven years of his life, shows up spinning tales of a prophecy. Not just any old prophecy either, but one in which Kellen plays a key role. Suddenly, Kellen finds himself on the run through a Celtic underworld of faeries and demons, angels and gods, not to mention a really ticked off pack of hellhounds, all in order to save the world from darkness. But will they make it in time?