In a world where spells have become subscription-based and accessible to anyone, Ryusei Segawa, a member of the Ministry of Internal Affairs' Spell Security Bureau, works to seal and regulate dangerous spells that threaten public safety. While on a mission in Chiba Prefecture, he encounters Urumi Namatame, a girl with a genius-level talent for creating spells—far beyond what ordinary users can achieve. What awaits them is a tale of modern sorcery, regulatory battles, and a fateful encounter that could reshape the world of magic.