Peter Jahrling, the top scientist at USAMRIID, has ORCON security clearance that gives him access to top-secret information of bioweapons. His most urgent priority is to develop a drug that will take on smallpox - and win. Eradicated from the planet in 1979, the smallpox virus now resides, officially, in only two high-security freezers - at the Centers for Disease Control in Atlanta, and in Siberia, at a Russian virology institute called Vector. But the demon in the freezer has been set loose. It is almost certain that illegal stocks are in the possession of hostile states, including Iraq and North Korea. Jahrling is haunted by the thought that biologists in secret labs are using genetic engineering to create a new superpox virus, a smallpox resistant to all vaccines.

USAMRIID went into a state of Delta Alert on September 11 and activated its emergency response teams when the first anthrax letters were opened in New York and Washington, D.C. Preston reports, in unprecedented detail, on the government's response to the attacks and takes us into the ongoing FBI investigation. His story is based on interviews with top-level FBI agents and with Dr. Steven Hatfill.