The city of Seattle is stunned when a deadly bacteria tears through a nearby Bible camp. Early tests reveal the illness is a form of meningitis, and the camp's residents are among its most vulnerable victims: children and teenagers. Facing a rapidly rising death rate, Seattle's chief public health officer, Lisa Dyer, and her team quickly take all steps necessary to contain the devastating outbreak. And when further testing reveals that the strain of the bacteria is one that caused catastrophic losses in Iceland six months before, Lisa decides to take a drastic step: she contacts Nathan Hull, vice president of a pharmaceutical company that is doing final-phase trials on a viable vaccine, and asks him to release it early for use on the city's population.