The Changeling — Morgan Richter

Still reeling from a devastating tragedy, Kit Garrett struggles to adjust to his fancy new prep school. When his estranged older sister Ivy starts undergoing a frightening physical transformation, Kit embarks upon a quest to save her. He follows Ivy into a cave near his school and finds himself stranded twenty years in the future, after a mysterious catastrophe has obliterated almost all traces of human life.

Accompanied by his nemesis Ashley, the star of the school's lacrosse team, Kit makes his way across a destroyed land in search of his sister. Defenseless and in way over their heads, Kit and Ashley face off against a succession of dangerous and bizarre creatures: vicious imps with a taste for human flesh, telepathic cockroaches, and a gorgeous but lethal glass dragon. While Ivy struggles to come to terms with her ghastly birthright, Kit unearths the long-buried secrets of his own dark past. Kit's mission becomes clear: rescue Ivy, find a way back to his own time… and save the world, if he can.