Australia undergoes a rebirth with the surprising assistance of an unknown benefactor. Dr Rachelle Rizzoli has spent an age attempting to correct the mistakes of her past, while her son longs for the day when they will come into contact with whoever is aboard the mysterious ships dumping their precious cargo to transform the once barren landscape into tropical rain forests in the north and grassy plains to the south. But all is not as it seems and their visitors are not alone.