This 4-koma manga describes the funny everyday life of the odd middle school teacher Rioko, her students, and the other people in her life. One day, she brings a little girl, Hano, to school as a transfer student. As if it's no big deal, she tells her students that Hano is not human. The students don't know what to make of this, but the class rep and the self-important student Shishio end up hanging around with the strange newcomer. Soon another new person arrives: Rioko's little sister Shion! Shion was raised as a boy in an isolated mountain village populated by the elderly. As a result, she's socially inappropriate and can't tell young men from women. She moves in with her older sister, and joins the class at school to learn more about society. Their daily life continues, filled with social awkwardness and comedy.