地球へ留学したアキツキと、月に残った後輩サクラとの、１年余りに渡る往復書簡集。

地球と月とが断交しておよそ１００年。
１世紀ぶりに再開された地球留学プログラムに応募し、地球へ渡り、さまざまな異文化体験をして行くアキツキと、そんな彼にあこがれを抱き、自分も地球へ渡りたいと願う後輩のサクラ。
３８万キロの間に、地球の工業生産を一手に担う衛星公社を挟み、二人は心の交流を続けて行く。
しかし、地球と月の関係悪化と、サクラの病気が、次第に二人の距離を遠ざけて行く……。

The one-year-correspondence between Akitsuki who went study-on-Earth from the Moon and Sakura, who remains on the moon.

After the break up of diplomatic relation between the Earth and the Moon, Akitsuki went to the Earth under the first scholarship program in 100 years.
And Sakura, who always has a little affection to him, writes letters to him, thinking that she could go to the Earth in the future.
But the political situation and the illness of Sakura's lung interfere her dream of staying in the Earth's university with Akitsuki.

(Written in simple Japanese)