Margaret Montoya 's actions at the end of Contagious might have saved the lives of many, however most consider her to be a monster rather than a hero. Since that time she has turned into a shut-in out of guilt, something that has torn apart her relationship with the CIA agent Clarence Otto. However now she is called forth to help fight against a new version of the alien microorganisms, one that was launched by the probe just before it was destroyed. Montoya and the others try to do their best to combat the microorganisms and help keep the general public aware, only for many to assume that this is either a coverup for something more human in origin or an outright fabrication. However as the book progresses things grow more dire and the world is plunged into an apocalyptic environment.