The Darkest Part Of The Forest by Holly Black, 328 pages
Hazel and her brother, Ben, started fighting the fairy monsters in their town when they were just kids. Ben's music kept the monsters enthralled while Hazel killed them. Their town has always coexisted with the fairies and usually only the tourists get in trouble. However, there is one fairy that lives as a human because, when he was a baby a fairy tried to leave him as a changeling. The human mother demanded her child back but kept the fairy also and since that time the fairies have been more active with locals also. Hazel, who made a deal with the fairies when she was ten, may be the key to stopping the terror that the fairies seem to bringing to their town, but only if she can figure out the mysterious riddles that someone has been leaving for her and Ben. This was a great fantasy that I would highly recommend to teens.