Jack Furness, a world-famous mountaineer, is scaling one of the highest peaks in Nepal when he slips and falls into a crevasse. In the snow he finds a fragment of skull preserved in almost immaculate condition, and on returning home presents it to his ex-girlfriend, Dr. Stella Swift, a paleoanthropologist at Berkeley. Stella is intrigued. The skull, when she examines it, seems to be a rare exam...