When 11-year-old Miyamoto Rebecca takes on the role of a new teacher for a class brimming with eccentric individuals, her cute appearance belies her fierce and sardonic nature. With her sharp tongue and sarcastic demeanor, the once-safe school environment is thrown into chaos under her unconventional leadership. Alongside her students Himeko, Ichijou, Rei, and a white rabbit that has grown fond of her, Rebecca orchestrates mischief not only within her own class but also against the neighboring class and their teacher, 'ojii-chan'.