After the asteroid impact 65 million years ago -- believed to have wiped out the dinosaurs -- Australia was set adrift on a lonely voyage in southern seas. With host Richard Smith at the wheel, NOVA travels this walkabout continent to uncover how it became the strange island it is today. Australia's many unusual creatures, like the kangaroo and the cassowary, tell a tale of isolation, change and resilience. Australia's long history has seen mountains rise and fall, seas come and go, and whole kingdoms of life triumph and disappear. In this final episode, NOVA races down the last 65 million years to the present day.