An ocean of humanity runs from a devastating force that no one can even see - they pour northwards over the Mexican border. A mighty nation falls... Sullivan town remains one of the last enclaves of civilisation. Greg Valdiva, a stranger to the community, has lost his city home and his mother and sister both died on the gruelling journey here. Beyond the township's ramparts humanity is undergoing a strange and terrifying transformation. Fearing contamination, Sullivan isolates itself, allowing no one in or out, under the threat of death. When Greg Valdiva helps hungry refugees, he is forced to flee. He joins a band of teenagers and discovers that the Earth has been overwhelmed by a new species of human beings. He and his friends are on the run; theirs is a ceaseless struggle for survival. Soon Greg will learn about the twenty-first century curse that has befallen humanity. And that this is the start of a war like no other as humankind plunges towards the abyss of total extinction. Is this the end? Or does humankind have a saviour?