Demons are natural disasters. No one knows why they appear or where they come from. They just do and when they do, you can just hide under the desk and pray to all the gods you know so they won't find you. The only force to protect humanity is a small group called ADA (Anti demon association) and their ace Alexander.

But Alexander is not quite bent on saving humanity (he would rather spend his time lazing at the beach) until he meets Nyla on one of his missions. could this weak understated girl bring out the hero in him? or the whole of humanity is doom to suffer from demons for eternity