Miiko is the protagonist of the series. She is an energetic fifth-grader and can be mistaken for a kindergartner due to her height. Miiko loves eating, which becomes a problem because she gets fat easily (as shown in much of the episodes). Her best friends are Shimura Mari (Mari-Chan) and Yuuko Ogawa. She's often found hanging out with her friends or fighting with a boy called Tappei who seems to like Miiko a bit but was too shy to say it to her himself. He called her names instead and sometimes got on Miiko's nerves