The story begins on the planet Arth, a haven for the survivors of the Old Empire. Due to heavy radiation, the inhabitants have been forced to live beneath the planet's crust for centuries. In recent times, the radiation has finally dissipated from the surface, allowing the population to unearth long-lost technology belonging to Arth's original settlers. The inhabitants of Arth have recently discovered two things: first, that they were once a colony world of Earth; and second, Endurium, a crystalline mineral that fuels interstellar flight.