Gaming Nexus writes: "Saying that Space Siege is Dungeon Siege in space would be like saying Gears of War is just a third person version of Unreal Tournament III. The games share technology, a similar control scheme, and similar perspective but that's about it.
In the future the Earth reaches out to the stars. Unfortunately for us we run into the Kerak while colonizing a planet. The Kerak realize that humanity isn't mostly harmless and decides to eradicate humanity not only from the planet but from the universe itself. They track humanity back to Earth and destroy the planet. Fortunately humanity sees it coming and manages to get a few large colony ships off before the planet is cleared out for a new interstellar highway. You play Seth Walker, a military soldier on the Armstrong, one of the ships who must help keep the ship and the last remnants of humanity safe so they can find another home (kind of a reverse Battlestar Galactica if you think about it)."