However...someone we never expected is intervening.Starting with the Hakurei shrine maiden, whose job it is to resolve incidents, the Moriya shrine maiden and others who know how to exterminate youkai undertook dealing with the problem, but the extent of damage was too vast, so now they lack sufficient manpower.These are no small threat to the humans in Gensokyo.Since the seal on Byakuren Hijiri was undone, demons began to appear in Gensokyo...While there are those among the demons who are friendly toward humans......there are also those who would do humans harm.