One day, a strange girl name Sou Akiyama (fondly called "Aho Girl" by her classmates) came to Azumaya middle school. She repeats any absurdity she hears, including calling her teacher "mama" and addressing the physical education teacher as "Mr. Karate" because he wears a karate gi during class. The school's student council and her classmates are fed up by her antics, but they are fascinated by her cheerfulness and her originality. The latter is even more so after she foils a plot by a group of "normal students" to fool around during class, which they thought was not possible to be done by Sou because she repeats every word she hears. Sou is more than just a silly girl who repeats everything she hears. She is a genius who solves problems in her original way. For example, when she sees students with long hair, she cuts it off with scissors because she's worried that they might get tangled in barbed wire or something.