Within a world where magic wielders known as 'Period' combat otherworldly monsters called 'Spiral,' we follow the journey of 14-year-old apprentice Period Haru from the Eighth Arc-end Division. Tasked with halting the Spiral's rampage, Haru finds himself thrust into an unending conflict. Yet, when a puzzling theft plunges his division into financial ruin, Haru and his allies are compelled to abandon their base. To restore their standing, they must navigate a series of challenging quests to establish a new foothold.