CDC scientist Dr. Susan Prescott is on a mission to find the holy grail of cancer cures and believes she's discovered it in the work of Vladimir Sokolov, a Russian geneticist whose lab was closed during the fall of the Soviet Union. Prescott and her research associate learn that Sokolov's re-engineered microbe cures many cancers. But after Prescott is shot at, her research associate murdered, and all the samples stolen, it's clear that someone will kill to keep the microbe secret. Atlanta Police Department Homicide Detective Nick Hunter is assigned the case. Working closely with Prescott, Hunter soon finds himself enmeshed in a romantic relationship with the beautiful doctor. The investigation takes a sudden turn when Hunter is called out to investigate a mutilated corpse—it's a female lab tech who worked with Prescott, and she wasn't killed by ordinary means. An unknown and deadly microbe has destroyed her brain and lungs. When Prescott reviews her deceased research associate's experimental data on Sokolov's microbe, she discovers a horrific secret: the microbe mutates into a killer. Even worse, Hunter learns that Sokolov's psychopathic sidekick has infected dozens of U.S. Senators with the microbe. While Hunter tracks the terrorist, Prescott races to develop an antidote. She has 72 hours before the senators' brains and lungs turn to mush. Will she be able to save them?