The game takes place in 2061. Halley's Comet has been approaching Mars for quite some time, and the nations of Earth send a mission to investigate the comet, as some form of life has been detected inside the gas of the comet.

The main character of the story, Musou Hayao, is a Japanese soldier-in-training and the second-youngest member of the mission.

Coincidentally his girlfriend, Eline Suleyman, is also a participant.