Bisuna, a descendant of the ancient Nanaba Kingdom, is driven to resurrect her ancestral kingdom’s former glory by harnessing the "Eye of Rainbow"—a fabled artifact capable of granting any wish. When the treasure is unearthed by Senbei Norimaki, Bisuna targets it, stealing the Eye from Arale Norimaki and her allies. Her theft sparks a high-stakes clash, propelling Arale’s group into a desperate quest to recover the relic. The conflict reaches its peak at Nanaba Castle, where Bisuna’s ambitions collide with their efforts. Her actions are fueled solely by her obsession to rekindle the kingdom’s lost power, anchoring the narrative’s central struggle around the artifact’s fate.