A family from Earth is flying through space when it crashes onto a plant based planet. Both the Mother and Father die leaving the baby who had been protected in a sleep chamber the only surviving member of the family. This planet is inhabited with aliens made out of plants.
A curious alien girl named Hazel finds the crashed ship and while exploring finds the baby and takes him home to her scientist Father Myriel. Myriel works for the planets government and uses his clout to acclamate the child into this alien society and the boy learns to act like them.
The scientist brings the crashed ship to his lab and studies it in hopes of learning about this alien human child and to learn about that culture that he came from. He finds out that his name is John and many other things from books and journals that were left. Over time John grows and starts seeing visions of a great plague that will befall the planet. So he and Hazel end up leading a group of aliens on a journey to save their civilization. Hazel ends up being John's protector since he's small and frail.
This story references and honors bits and pieces of many great books like Tarzan, Watershipdown, and many others.