Humanity was on the edge of destruction years ago because to giant magical armored insects that had become too powerful and hostile to manage. Because of these giant bugs, humans no longer live on the earth, preferring to live in floating cities. However, this does not mean that everything is lost, since these creatures are being fought by wizards from prestigious floating wizard institutes. Kanata Age is a young guy who has been called a traitor while being hailed as the "Black Master Swordsman." He gets the opportunity to redeem himself by directing squad E601, which seems to be in difficulty. Misora Whitale, Lecty Eisenach, and Rico Flamel are the three girls that make up the group.