Symbiogenesis

Not far from now. Humanity survived from the contaminated land and lived on the "Floating Continent," humanity's last safe haven. People who live without conflict, while regaining their former civilization, However, it is shattered by an attack by a "dragon" that shakes the existence of the "floating continent". While repelling the attack of this "dragon", humanity solves the mystery of the birth of this world, We are faced with choices to lead this world to an ideal future.