Doctor Sara Kingsley, age 35, was the head physician at the Darwin Genetic Research Station in 2365. She led an experiment to produce "superhuman" children who would be immune to virtually all forms of disease. During the experiment, the children's advanced and proactive immune system, which sent out airborne antibodies to destroy potential infections before they entered the body, interacted unexpectedly with an alien virus and became dangerous to normal humans, mimicking the effects of rapid aging. The whole of the station became infected with the disease.