In brief...

The damaged and battered body of the galaxy has been infected. The wounds caused by the Armageddon War left a place for darkness to grow. The Syndicate, warlords, and remnants of the invading Nagatha have taken root in the rim worlds. Those left behind often turn to the Syndicate or seek to make their way through the gray. A fog of governments who stand only as puppets to those pulling their strings. The star marines, the SAINT police force, and others seek to restore the law of the land but they are the few against the horde. Standing on the brink with just a push the rim can slide into the abyss. Are you SAINT or Synner, choose before the galaxy chooses for you.