This book is about a man named Valentine Michael Smith who is a human, but he was born on Mars. He faces great struggles and does not "grok" or understand a lot of things about the Terran civilization but tries to learn and is eventually taught by his friends or water brothers.

The setting is in the distant future shortly after World War III, a manned spacecraft the Champion is sent to Mars searching for its predecessor the Envoy, which lost contact shortly after landing on Mars. The crew of the Champion finds Valentine Michael Smith, and they also make the first known contact with an intelligent life, the Martians, who agreed to let Valentine Michael Smith go to Earth to live among his actual people.

Once Valentine Michael Smith lands back on Earth with the Champion and its crew...