2538 A.D. With technology so advanced, and the population of Earth reaching incredible numbers, the increasing need to expand cities has become painfully obvious. Colonization of terraformed planets Venus and Mars was successful, and the people of Earth are now expanding into unknown territory in space, however the ambassador of the Lu’menians, an alien race, has withdrawn from United Nations talks with Earth and surrounding colonies, for unknown reasons.

The year is 2544. Earth and her colonies are in a state of war with the Lu’menian people, after the destruction of the Mars colony which wiped out 92% of the population, leading to a massive influx of refugees arriving on Earth. The UN Space Corps has conscripted young men and women into the forces in their fight against the Inarians and their machina pets, however the warfare is strained and precariously drawn-out. The UN Space Corps, and Earth itself, is at risk of being destroyed.