Ten years before she was murdered, Dian Fossey, subject of the film "Gorillas in the Mist," was one of the naturalists featured in this documentary about primates. Fossey studied the mountain gorillas of central Africa. The other scientist, Birute Galdikas-Brindamour, studied the orangutans of Borneo. Both worked towards the survival of two species severely impacted by the encroaching demands of human beings. Footage is included of Fossey and Digit, one of the many gorillas she befriended and learned from in her years of fieldwork and study.