Okamoto Ako came to Kibou Academy to undertake her teaching practice, but she was met with a series of lewd pranks by the protagonist, Ishibashi Yuuji. Ako, who was raised overprotectively like her older sister Riko, is naive and has a serious personality, causing her to confront Yuuji's lewd pranks head-on, even as an educator. At times, she confides in her sister, who's also a teacher, but it remains to be seen whether she will receive practical advice. The fate of Ako's teaching practice, which involves her sister, is unclear as Yuuji's chaotic school life filled with wild delusions begins.