In 2031, the world goes through a drastic change after a next-generation quantum reactor fails catastrophically in an incident known as the "Xianglong Crisis."The energy that springs forth from beneath the ground swallows up city buildings and covers the earth,eventually leading to the emergence of new organisms called B.R.A.I. that are both organic and mechanical.Seven years later, Xianglong has been reborn as the fortified city of Neo Xianglong.It is the last bastion of hope for humanity against the rapidly evolving B.R.A.I. threat that has pushed mankind to the brink of extinction.Leon, Chloe, Queenie and Doug are led by destiny to gather at Neo Xianglong.Cecile, Cain, Jay and Gren welcome them into the defense force.The special unit Pandora is born to fight for the survival of humanity.The hope of everyone lies in their hands as they enlist.