The fourth volume in F. Paul Wilson's series of novellas about a time and place very much like our own except that the science of genetics is decades more advanced, wherein the fates of a set of humans and a race of recombinant chimpanzees "upgraded" with human genes are inextricably entwined.Book Four: Zero opens with the desperate search for Meerm, the mysterious Sim who carries a secret that can change the world, and closes as the even more mysterious Zero exposes his true self.