Viewers join NOVA as the program explores a recently discovered, ancient cave beneath Australia's Nullarbor Plain. Known as one of the country's most barren landscapes, this cave has remained untouched for thousands of years. Discover the preserved remains of unknown kangaroo species as well as the first complete skeleton of the Thylacoleo carnifex, the largest carnivorous marsupial. Scientists recover the remains in order to examine the past of these creatures. Features described video.