|...the story goes here. Basically, the gates cause
the raw Chaos Stuff from hell and whatnot to spill into our dimension.
Wacky things happen, sometimes good, more often not. Some things become
easy, others hard. Humanity has almost become extinct. Only a few secret
pockets in hidden underground complexes (that haven't been breached by
the hell-spawn) exist. What few humans do live above, scavenge for
everything. From spare parts, to food, clothing, weapons and water.
Scavenge is the name of the game in this dark, new world.
Recently, parts of "reality" have been slipping away. People, houses, even whole towns have simple disappeared. The theory is that they "slipped" into the demon realm. The more demons and hell-spawn that appear in our dimension, the more our dimension starts to appear (re-locate might be a better word) in Hell. Something must be done, and done fast.
What it all boils down to is this: you must stop the main Influx Gate before all of reality as you know it slips into total chaos.