summary: An animal lived in rich nature peacefully. But suddenly, environmental disruption occured. The rich nature disappeared, and many buildings appeared. The animal lived in it, but his phisical condition became bad because of bad environment.
main point: The problem of environmental disruption
What's happening in the end: When the animal's condition were bad, a mysterious creature helped him. The creature brought the animal away where the environment is good. After that it could live in rich nature again.
