When the director of a Los Angeles health maintenance clinic succumbs, along with seven patients, to an untreatable--and virulently contagious--virus, Dr. Melissa Blumenthal is assigned by the Centers for Disease Control to investigate.

The California case is merely the first in a burgeoning series of outbreaks that occur in unrelated geographical areas but with puzzling commonalities: The locations are always healthcare facilities, and their victims are only physicians and their patients.

As her investigation takes increasingly bizarre turns, Melissa finds that behind the natural threat lurks a far more sinister possibility--sabotage--and soon finds herself facing the wrath of a powerful cabal, sworn to achieve its aims, no matter what the cost in human life--including Melissa's.