From the introduction:
A world without hope. A war without mercy. That's the world we live in. The air is poisonous. The seas are dead. Mutants roam the poisoned wastes. Mechanized barbarians plunder the scattered settlements. Sentient death machines stalk the survivors. The ultimate power source, drakonium, is becoming rarer and rarer with each passing year. In the last of the megacities, five warrior civilizations prepare for doomsday.
Somebody has to hold it together. That's what we're for.
Welcome to the Rangers. Welcome to Firebase Alpha.