A young girl named Kurumi Mirai has dreamed of becoming a magician ever since a mysterious encounter in her childhood. She studies relentlessly and earns top marks on the mock exam for the prestigious Rettoran Academy of Magic, the nations premier institution for training state-certified magicians. On the day of her results, her hopes are crushed when she fails the entrance exam for the elite Magumi magic training program and is placed in the standard program instead, a track not intended to produce magicians.

Just as Kurumi begins to abandon her lifelong dream, her new homeroom teacher for Class 1, a childlike woman named Minami Suzuki who is herself a powerful state magician, makes a startling declaration: she will teach every student in the standard class to become a magician. This promise rekindles Kurumis ambition and sets her on an unconventional path. Unlike the Magumi students who cast spells using modern magic notebooks, Minami introduces the class to ancient magic, which requires drawing spell arrays by hand. As Kurumi and her classmates struggle to master this forgotten art, they begin to uncover secrets about the school, the gatekeeping nature of modern magic, and their own hidden potentials. Kurumi discovers she comes from a bloodline possessing powerful magical talent, and her placement in the standard program was not a failure but part of a deliberate plan orchestrated by Minami to awaken this ancient magic within her. A deep and supportive friendship develops between Kurumi and her classmate Yuzu Edel, a prideful young woman from a distinguished magical family who is also bitterly disappointed by her placement in the standard program. Together, they and the rest of Class 1 confront the darkness festering within Rettoran Academy, battling monstrous entities born from uncontrolled magical energy. The story culminates in a final confrontation where Kurumi and Yuzu, now proficient in ancient magic, fight against a powerful adversary connected to the schools hidden history, ultimately sealing a dark rift threatening the academy. The original web novel features significantly darker and more complex worldbuilding than the subsequent anime adaptation, including concepts such as magical people requiring a transformation to use magic, vaccines related to this process, and the cost that becoming a magician means losing the ability to have children. Kurumis character is also notably different, possessing a more cynical and calculating personality along with precognitive abilities for weather and test answers, forming a stark contrast to the more openly optimistic and emotional portrayal seen in the anime.