Kaguya was found in a bamboo forest when she was just a baby, and she was so small, about the size of a thumb, that her parents knew that she was not human.
They raised her as their own, but one day her real parents came for her. She went with them unwilling back to their home, the moon. She pledged that one day she would return to see her Earth parents again...
The story in Kaguya takes place after she escapes from the moon and once again returns to Earth.