In the Aftermath of A Deadly Arson Fire at DyMar genetic research laboratory, the discovery of a disease-ravaged body in the ruins leads FBI agents Fox Mulder and Dana Scully to fear that a man-made plague may be on the loose. To stop the lethal virus, the agents must discover how it works. The answer may lie with Dr. David Kennessy, DyMar's genius researcher, and his experiments with "biological scouts", microscopic machines injected into the bloodstream to repair damaged cells. Kennessy's work could theoretically provide a cure to almost any illness or injury -- in fact, could uncover the key to immortality. But did the pressure to save his own leukemia-stricken son's life lead Kennessy into an area of futuristic biotechnology beyond his control?

Mulder and Scully can't ask Kennessy, who died in the fire, and as they search for answers, they find themselves opposed by enemies who have all the resources of the government -- even perhaps the FBI -- at their command. Enemies who will stop at nothing to ensure that the secret of immortality falls into the right hands -- their hands.