In the 22nd century, humanity has achieved world peace. The United Earth Space Alliance (UESA) was able to fully concentrate on space exploration. In the year 2147, the first colony ship was launched towards the asteroid Theta-2. However, the second vessel, carrying the colonists, encountered a terrifying disturbance in space. Alien ships emerged from what later became known as "The Void", and attacked the colony ship; the subsequent fate of ten thousand people on board was unknown. Humans constructed the inter-dimensional starfighter Radix, and sent it through The Void, in a desperate attempt to face the alien threat.