Taking place in the realm of Luminasia, the tale portrays how prominent nations exploit their smaller counterparts to gather Hostia, a kind of mana in the form of crystals, produced by the World Tree. It depicts the journey of the protagonist and Ad Libitum, a guild, as they delve into the mystery of red smoke. Despite the common belief that it is a manifestation of the Descender, capable of fulfilling one's wishes, it can actually transform the physical forms of living creatures.