An intense scientific debate has ignited around a quiet but extraordinary family living in rural Turkey-a family with five adults who walk on all fours. Since bipedalism has long been considered one of the defining characteristics of modern humans, such a discovery raises fascinating questions about genetics, society, and the evolutionary history of our species. Is this the anthropological find of the millennium, or simply a unique medical case? NOVA sets out to unravel the controversy and meet the individuals who have captured the imagination of scientists around the world.