Nova and National Geographic present exclusive access to an astounding discovery of ancient fossil human ancestors. Deep in a South African cave, a special team of experts has brought to light an unprecedented wealth of fossils belonging to a crucial gap in the record of our origins that spans the transition between the ape-like australopithecines (such as the famous Lucy) and the earliest members of the human family. The film describes the 2013 discovery, and later excavation, of the fossil remains of Homo naledi, an extinct species of hominin assigned to the genus Homo, found within the Dinaledi Chamber of the Rising Star Cave system, located in the Cradle of Humankind, South Africa.