The game world is made up of 3 different realms, the "Underground World" where mechanical and magical sciences advance on equal footing; the "Aboveground World" made up of knights and mages; and the "Sky World" where gods and devils coexist. The main character, "Kuon", is a student of a military school in the Underground World who loves to adventure, always embarking on adventures when his curiosity is piqued. One day, he encountered a mysterious girl in the hospital he was sent to for treating injuries he sustained, and that is how the story begins...
