After being devastated by a nuclear war, the Earth is a planet with a population of only 4 million, overrun by a variety of mutated lifeforms. Worse, much of the Earth is now owned by the Vegans, a race of blue-skinned aliens who see the planet as a tourist location. Conrad Nomikos, the first person narrator, is a man with a past that he would rather not talk about who has been given a task that he would rather refuse: to show an influential Vegan around the old ruins of Earth. But Conrad suddenly finds himself the reluctant protector of this alien visitor when attempts are made on the Vegan's life. Conrad knows that keeping the Vegan alive is important—but now he must find out why.
Conrad now finds himself pitted against a group of Earth rebels that includes an old comrade-in-arms and an old lover, neither of whom can understand why he would want to protect one of Earth's subjugators. He is aided by another old friend and an old man who is actually one of his sons. It is eventually revealed that the Vegan he is escorting has been charged with the final disposition of the planet Earth. The Vegan in his turn is confounded by Conrad's actions. Ostensibly there as a tourist to see Earth's sights, he is horrified to find that Conrad is having the pyramids of Egypt torn down, more so when the immortal explains that the process is being filmed, and that the film will be run backwards to simulate the construction of the pyramids. Along the way it appears that Conrad's beloved wife is killed in a natural cataclysm.
At the end, the rebels realize that Conrad has been fighting to protect the Earth in his own way. Through actions such as the deconstruction of the pyramids, Conrad makes the Vegans see that Earthlings would rather destroy the planet's riches than see them fall into the hands of others. In the final battle to protect the Vegan, Conrad's wife appears to deliver the decisive saving blow. The Vegan sees the mettle of which Conrad is made, and decides to leave the planet in the possession of the one being with the longevity, power and moral fiber to do well by it. Conrad finds himself the owner of Earth.