after an asteroid was discovered in the seventies and turned in to an official new moon in the eighties. an accident happened at the turn of the millennium, sending nuclear weapons at the new moon and turning it to a ring of dust around the planet.
this ring slowly falls on to the surface and whoever gets exposed to its content transforms in to a monster.

the substance that fell from the skies that day was named Compound Y2K.
to combat the transformed people named The Fallen the whole world developed the Global Mech Initiative to combat these monsters by building metallic monsters of their own .

this is the story of a team of pilots who drive said metalic monstrosities and their attempt to save Paris from an invasion of fallen