The Professor eagerly awaits the arrival of a colleague, Professor Doyle. Upon arrival, all are surprised to find that Doyle is a woman. Professor Robin Doyle had come to Africa to study Keewazi's tribe with the Professor. While they study, they find some of the older men to have quite startling ages, and learn about a great fountain. Professor Porter, who feels he's too old for Robin, secretly sets forth to find this fountain.