(1) short summary:
There is an animal that likes nature. He also considers important it. One day, however, the nature is suddenly destroyed (by the civilization). Gradually, he becomes less energetic in no natural environment. At last, he can go to the environment surrounded nature.
(2) my opinion:
I think the theme of this film is "how great nature is" and "people should value nature." Nowadays, people all over the world overestimate their own abilities. We can't exceed the power of nature. We, however, are destroying nature just as we like. We are able to live now thanks to nature. Recently, lots of people including myself forget it. I realised the importance of nature again through this film.
(3) the end of this film:
I think the animal leads a happy life surrounded by nature with his friends. It can be a hopeful future.