It has been three months since the doomsday cult unleashed the genetically engineered Berlin C virus, and today most of the world is dead or dying. Among the living are a group of hospital patients and their nurse, Marie Alexander (Maria Conchita Alonso), who have survived because they were already under quarantine when the virus struck. They are running out of food and fuel when a soldier arrives with a new vaccine from the Center for Disease Control. But, there's only enough for three doses and it will take three days for the vaccine culture to develop enough to be effective. It falls to Marie to maintain order until the vaccine is ready, and to decide who will get injected.