The first Earthling YZ, a youthful would be educator from a distant planet, meets is a dog. Being pure energy, YZ enters the dog's body to begin his task of teaching Earthlings how to love each other and preserve their planet. Scolded by the Director for entering a dog instead of a human, YZ has to remain in the animal's body until it dies. Thereafter he is able to enter various human bodies in his quest to direct them on how to live well. Though he has some successes, he feels like a failure and begs to return to his own planet. Once there, he advises the Directors on the quality of Earthlings. But what is he to do next? The new task he sets for himself could surprise and delight young readers..