In the waning days of World War II, an American destroyer sinks a Japanese submarine near the coast of Korea carrying bombs packed with a deadly hemorrhagic fever virus. Intended for a last desperate attack on the United States, one of the bombs survives the fire and sinks to the sea floor. Ocean currents slowly carry it south while its seals gradually deteriorate.
Three generations later, CDC virologist Dr. Kristin St John investigates a suspected outbreak of the Reston stain of Ebola in the southern Philippines. The only type of Ebola that spreads through the air, the one thing that prevented a staggering death toll when the first outbreak killed monkeys near Washington D.C. in 1989 was its inability to infect people. Kristin's fear that the Reston strain has acquired this capability seems to be realized when people start dying in nearly villagers. Later she learns the new virus is a transmuted cross between the rare Reston strain and a type of hemorrhagic fever that killed hundreds of American soldiers during the Korean war.
Rishad Zharmakhan, an al-Qaeda Ph.D virologist, learns of the new virus and travels to the Philippines to obtain samples. CIA investigator Colwin Lark interviews Kristin concerning its potential to be turned into a bioweapon. As their relationship becomes romantic, Zharmakhan is busy trying to make that nightmare real.
With the CIA closing in, Zharmakhan destroys his secret lab in Kazakhstan and flees to Jakarta, establishing a larger facility to produce his far deadlier version. The CIA sends cruise missiles to take out Zharmakhan and his new lab. When Kristin learns of the attack, she tries to stop it, but it's too late.
The unintended consequences of the explosions are far more horrific than even Kristin had suspected. With no vaccine and no cure, is the end of humanity at hand?