Mugentou

Mugentou (無限島, lit. "Infinite Island") is a manga series by Yuukei Nakagawa.

Plot
Kooru, a young elementary school girl from Tokyo, is suddenly given the news that she will be moving to Mugentou along with the rest of her family. It's a mysterious secluded island lost to the times and cut off from the rest of civilization. It lacks the many technological advances but has abundant natural life and beauty complemented with many magical and paranormal phenomenons.

Follow along and see where Kooru's imagination will take her.