Despite advances in modern medicine, viruses continue to kill millions of people every year. This documentary focuses on influenza, smallpox and Ebola, among the most lethal viruses ever to have plagued mankind. Three years in the making, the three-part series goes around the world to understand how viruses have shaped health and history, the biological and social impact they have on global society, and the incredible work that is being done to combat them. Interviews with officials from the Centers for Disease Control and Prevention, World Health Organization, National Institutes of Health, and National Institute of Allergy and Infectious Diseases are included, plus insights from homeland security officers and biosecurity experts.