When terrorists infiltrate the U.S. Department of Agriculture's Food Safety and Inspection Service, people start to die. Joined by his friend, Charlemagne Tainter, Agent Darrell Metz begins his quest to track down and eliminate the Defenders of Islam terrorist cell. Complications arise when Austin Logan learns that Sean Dougherty, the man who murdered his wife, is still alive. Convinced that Dougherty is now an assassin in the employ of the Defenders of Islam, Logan travels to Detroit to seek him out. When Logan's thirst for vengeance threatens the success of Metz's investigation, he is accepted as an ad hoc member of the bio-terrorism unit. Against a backdrop of assassinations, car bombings, and shoot-outs, the bio-terrorism unit races the clock in an attempt to track down several shipments of food adulterated with a deadly botulinum toxin.