After finding a mysterious crystal, Coven discovers he has a mysterious ability that lets him see the percentage of what might or might not happen, based on simple questions he asks. With this strange power in hand, he tries to use it to his advantage as much as possible in a world where powerful Mechas can use magic, being powered not by electricity but by mana, in a unique encounter between magic and high technology. The beginning of the story is quite introspective, featuring plenty of psychological conflicts as Coven's universe is gradually introduced. This ranges from a prestigious academy that trains only the most skilled individuals for Mecha piloting to an unknown global threat that slowly invades Earth and distributes monsters across the globe. These creatures appear in remote areas and ruins, waiting like dungeons to be explored with the aid of those powerful and mystical robots.