Exposed to the horror genre at an impressionable age by Theo, his equally troubled half-brother, freshman Joe Sheffield has only recently begun to control his obsession with all things grim and gruesome. But when two of his best friends move away, and his last best friend gravitates toward a new set of friends, Joe feels his old phobias returning with a vengeance, even as he is drawn to Gina, a mysterious bird-like classmate with her own dark secret. Discovering that several cats have disappeared within a single day from his principal's neighborhood, Joe concludes that something predatory has moved into the "puzzle trees," those decaying woods that lie between his principal's house and his own. When Theo pays him a surprise visit, the half-brothers go hunting. Their astonishing discovery opens the door to yet another mystery, one with possibly dire consequences, which Joe must face alone.