By the year 3000, Humans share the galaxy with several other sentient races in the form of a Galactic Commonwealth. While each race's views and philosophies differ, the galaxy is largely at peace and trade between worlds flourishes. Economics and political competition replace open warfare in the Galactic Commonwealth ... for a time.
On the outskirts of the galaxy, a new race suddenly appears. They become known as the Klissans, and with their massive fleet of ships they storm the worlds of the Commonwealth without mercy or negotiation. To deal with the threat, the Galactic Council is assembled and a decision is made to create an all volunteer force of Rangers to combat the Klissans. The Rangers are given complete freedom to act in any way they choose and come from every race in the Commonwealth with the singular mission to eliminate the Klissan threat.