Humanity faces complete annihilation after nukes are launched all over the world at the end of WW3. A diety intervenes moments before the bombs explode, preventing the destruction of all life remaining on Earth. This action isnt without a price though, as the diety gives humanity a chance to survive by placing them in a trial of its own making to prove their worthiness. Thus beginning the Era of Summoning, and everything humanity knew is turned on its head. Suddenly the world revolves around summons being used to fight monsters hellbent on wiping out humanity.