Tsuki no Sango月の珊瑚; 月之珊瑚; Coral of the Moon

The story takes place in approximately the year 3000, when humankind arrived at the peak of its civilization, but is loosing it's will to keep living. It follows a girl, called "princess" by those around her, living on a small island with a fifty person colony and a shinning coral reef. She is descendent of Moon people, and it focuses upon how her ancestor supposedly came to Earth.