Do you know who has been living next to humans for thousands of years? These are a small people, guardians of the Green World, who take care of every tree and stream. Previously, there were much more guardians than now, because the place of meadows and forests is taken by cities and highways.

So in the hollow of the old ash tree there are only three of them left - Raincoat, Moss and Heather. And the eldest of them suddenly began to disappear. What happened to him? And how can I help him?

Three friends are forced to leave their beloved home and go in search of an answer. They are led by animals, birds and stars. They say that at the roots of an ancient oak tree, near a ringing stream, their relatives live.

But soon the friends understand: they will have to overcome a much longer and more difficult path - to the huge, noisy and dangerous Human Hive...