After a nineteen-year-old male dies on a flight following a raging fever and violent convulsions, CDC epidemiologist Dr. Kayla Martin and her partner Carl Ratner consider the frightening possibilities -- the reality of the bird flu, the probability of a biological attack, or worse, a new virus they can't control. But by the time the passengers of the flight are filtered into the ward of a local hospital, the infection is already poisoning sections of Los Angeles, unbeknownst to each victim who passes it on.

As the epidemic worsens and the death toll rises all over California, the governor and mayor have to find a way around their political differences so that they can make tough decisions dealing with the blackmail scheme, as well as a frightened populace and all of the problems associated with a widespread and deadly epidemic.