An Anthrax-like virus begins striking Federation citizens of mixed alien and human heritage. Mob violence ensues as the panicked residents of Archaria III lash out at those they believe responsible.
Captain Jean-Luc Picard and the crew of the USS "Enterprise", in the first year of their on-going mission, are dispatched to the troubled planet to deliver humanitarian aid. But when a crew member succumbs to the disease despite the strictest sterlization procedures, the "Enterprise" must race against time to find both the origins of the virus and a cure - before the disease can spread throughout the galaxy and claim the life of Deanna Troi!