For 26 years, we've been at war. During the event known as 'The Descent', we were invaded by otherworldly beings known as the Enlightened, possessing grotesque and alien forms, they annihilated cities and countries in their wake. Today we have lost 97% of all mankind, and every year the number of lives lost only grows. The people remaining, fight. Latched on their last glimmer of hope, the Mech Runners, brave pilots controlling colossal humanoid walking battle machines. One so-called Mech Runner, Aurora's life takes a dramatic turn when she stumbles upon an enigmatic and powerful mech crafted from the very beings that have thrown the world into chaos.