Hoshi no Koe, using full 2D and 3D digital animation, is a story of a long distance love and mail messages between a boy and girl. Set in 2046 after the discovery of the ruins of an alien civilization on Mars, man has been able to make leaps in technology and is planning to send an expedition into space in the next year. Nagamine Mikako and Terao Noboru are junior high school students. However, while Noboru will be entering senior high next winter, Mikako is selected to join the space expedition.