*UPDATED 22 Oct 07 - When someone dies - they stay dead. Continuity problems fixed :)
It is the distant future. The Sol Federation is a central, slowly expanding empire, spreading forth from the Earth. Out in the far reaches, frontier worlds have banded together to form their own pocket empires, desiring independance and living harsh frontier lives on desolate worlds.
In the early years, the Sol Federation provided food and material support to frontier realms, but that has changed. Now they will only offer support if such realms join the Federation. Rather than give up their independance, many frontiersman have become pirate raiders, entering the borders of Federation space to steal supplies from outposts and borderworlds.
On the planet Mesarius V, the Armed Forces of the Sol Federation (AFSF) keep constant vigil against raiding forces. As the pilot of a Mechanised Assault Unit (M.A.U.), a twenty ton walking war machine, you are one of the defenders of Mesarius V. It is your duty to engage raiders who land on the planet surface, and to help drive them back to the frontiers empty handed.
However, a threat of a different nature is approaching your world, and for a change, it may be more than you, and the entire armed forces of Mesarius V, can handle...
(This is possibly an 'introduction story' for a series, depending on how much people like it.)