The Doom 3 story is set in the year 2145 on the planet Mars, which immediately tells us that there's not going to be too many out door scenes! The planet is home to an experimental science base owned by the worlds biggest conglomerate the 'Union Aerospace Corporation'. The scientists at UAC are 'taping into the very fabric of the universe and beyond' making discoveries that will change human existence, but then something goes wrong (of course). A wave of demonic entities are released, and with it some pretty scary characters.