Frank Plummer is a Canadian scientist studying AIDS, and since 1983 the centre of his work has been a clinic for female sex workers in Nairobi, Kenya. Plummer discovered that a small percentage of the women who came to his clinic, like 37-year-old prostitute Hawa Chelangat, did not become infected with HIV. He believed a vaccine for the dreaded disease might come from duplicating whatever it was that made these women immune. This film tells of a scientific quest, and also a human story of the unlikely partnership between a Canadian doctor and a Kenyan prostitute.