What kind of sorcery could shatter an impenetrable barrier...? A fantasy × mystery unraveling the unknown, with an immortal girl as the test subject! The protective barrier [Aegis] can block every spell once it has been learned. But its portable version, [Harmonia], was broken by an unknown form of magic. Jond, the head of the Barrier Enhancement Division at the Magic Research Institute, along with his three subordinates, begins experimenting on an immortal girl in order to uncover the truth behind this mysterious sorcery... A unique blend of fantasy and mystery begins!