Western Australia's red rock outcrops hold a record stretching back roughly four and a half billion years, to shortly after the planet's formation, and this opening episode of a four-part NOVA series uses that record to trace Earth from a molten, airless world to the first stirrings of animal life. Host Richard Smith travels to ancient formations in the outback, where geologists read the earliest evidence of oceans, continents, and atmosphere directly out of the stone. The film follows the rise of stromatolites, mats of bacterial slime that spent hundreds of millions of years pumping oxygen into an atmosphere that originally had none, a slow chemical shift that eventually made complex, oxygen-breathing life possible. That transformation sets up the Cambrian explosion, the sudden diversification of animal body plans that the series treats as the payoff of everything shown before it. Scientists appear throughout explaining what specific rock layers and mineral traces reveal about conditions billions of years old, using Australia's geology as a physical timeline for the planet's early history.