For the first time, humanity is about to be snuffed out by the marauding forces of the dark legion. Algeroth's evil forces emerge from their portal and establish citadels across the solar system.
The Megacorporations, desperate to retain their power, unleash the Doomtroopers to cleanse the solar system of the dark legion. The Doomtroopers' mission -- to annihilate the dark legion, and force Algeroth back through his portal, trapping him in the Dark Symmetry.