ZAK KILLIAN HEARS A VOICE¿ A guardian angel? A ghost? No, it can't be. But then the subway platform begins to flood, and the voice warns him to run! Soon Zak and his best friends Moira and Khalid find themselves in an alternate universe that is both familiar and horrifying. As Zak unravels the mystery behind the voice, he faces decisions that may mean the end of their world at home - if they can even get home! In his most propulsive and heartfelt book yet, acclaimed author Barry Lyga explores the depths of friendship, the bonds of family, and the nature of the universe itself.