Akane Satomiya and Aoi Satomiya are sisters who go to Hamazawa High School. However, older sister Akane is the homeroom teacher and younger sister Aoi is the student. To make the matter more complicated, Aoi is tall and sexy while Akane is small and cute. Their behavior is questionable, but full of sisterly love! In addition, there is another teacher who is a little too full of her looks, and a class rep, a beautiful girl, who is dedicated to karate. Together, the four of them spend some really fun times in school!