What would happen if the world were ending? When a catastrophic event renders the earth a ticking time bomb, it triggers a feverish race against the inevitable. An ambitious plan is devised to ensure the survival of humanity far beyond our atmosphere. But unforeseen dangers threaten the intrepid pioneers, until only a handful of survivors remain. Five thousand years later, their progeny - seven distinct races now three billion strong - embark on yet another audacious journey into the unknown, to an alien world utterly transformed by cataclysm and time: Earth.