The Sun: Key of Heaven tells the story in the year 2050, the sun unleashes a tremendous amount of energy into space. A wave of power will plunge human civilization into chaos for centuries. Although scientists had predicted this, the whole world ignored them.
And the consequences are regrettable for all mankind. All from old, young, big and small are all affected by a layer of fog that makes them cancerous and everyone is slowly dying, only a few people heed the warning have built dungeons from before can escape this nightmare. The battle for survival begins here!