The wizards create a series of balls of matter in space, and give one of them a Moon (accidentally). This stabilizes the ball enough that, over a score of millennia (the wizards can skip over vast periods of Roundworld time, allowing them to view the history of the universe in less than a month), blobs of life emerge, ready to begin evolving into more complex forms. The book also features a fictional crab civilization and the dinosaurs (both of which are wiped out by comets/asteroids colliding with the earth), before jumping ahead to when an advanced civilization (presumably humans) has evacuated the earth due to an impending natural disaster.