The book starts out in space on a large ship heading back to earth. Humans have been gone from earth for a very long time and want to see what remains of the planet.
The reason humans left earth was because the earth was going to pass through the tail of a great comet and scientist thought that all life would end. Unfortunately, not everyone could go and so only the scientists, the rich, and politicians got off planet before the comet came.
Since being in space, human technology has advanced considerably. They have spread throughout the galaxy and encountered many other species. Several of which they have had wars with and won with the exception of one species reminiscent of huge earthworms which are the only aliens that defeated the humans.
Upon arriving back at earth, they find that there are life forms on the planet. The humans decide to send just one man to the surface to begin exploring and learning what had happened to the humans that were left behind.
The explorer learns that the humans left behind did not all die. The earth was devastated by the comet and it changed the face of the planet with volcanic eruptions, earthquakes, and other disasters but it did not end life. In fact, it transformed those humans that survived.
After the earth passed through the comet’s tails and was transformed, humans on earth acquired the ability to shape change and had psionic powers to create objects with their mind just by thinking them.
At first this new power seemed like a gift, however, overtime, the humans on earth realized that some were stronger than others and conflicts escalated until the strongest of all took control and rules were instituted. One such rule was that by the age of 18, all humans must take on one form of their choosing and never shape change again. If you were caught changing, you were exiled to a remote island with all the other shape changers.
Also, creating things with your mind was not without cost. There is only a finite amount of matter and energy on earth. Every time something is created with the mind, it drains a little bit of life and energy from the natural world. Therefore, creating things with the mind was also curtailed.
The explorer also learned that those left behind resented and hated those that left earth because they felt abandoned. This hatred has only grown over time. The humans on earth want to be left alone and the humans in space want to stay. This eventually leads to conflict and the earth humans and the space humans begin to fight, technology versus psionic power. The explorer that came to visit earth sides with the earth humans to fight against the humans from space with technology. He creates a military force from the exiled shape shifters. He teaches them how to fight and encourages them to use their shape changing ability to overcome the advantages of technology.
We also learn a secret about the two most powerful earth humans. It seems that they obtained their great power by going to a forbidden place on earth that focuses the effects from the comet. The book describes the place as a bowl shaped place that sounds much like the Arecibo observatory and radio telescope.
The culmination of the book is when the wife of one of the main characters, who is hiding at the forbidden place, gives birth and the child is a mutated human that grows to adulthood in just a few days and has incredible psionic powers including telepathy. This new human takes over the planet and demands that all children be born at the forbidden place and the beginning of a new human race is spawned.
The super children then want to move into space and start to create space vehicles. When the leader asks the main character from the space humans where the best place to go in space is, the human tells him. However the super child reads the space humans mind and thinks he is lying. The super child misreads the human’s mind and goes to the planet with the worm-like aliens by mistake.
