In a cheerful and somewhat bizarre elementary school classroom, the students are greeted each morning by their homeroom teacher, Unko-sensei, a friendly and humorous humanoid pile of feces. Despite his unconventional appearance, Unko-sensei is a dedicated and effective educator who uses laughter and playful antics to teach his young charges. The setting is a typical Japanese primary school, where the daily routine is regularly turned upside down by the teacher's unique perspective on the world.

The storyline revolves around the daily adventures and lessons in Unko-sensei's class. His primary goal is to impart essential life skills and social etiquette to a diverse group of children, each with their own distinct personalities and behavioral challenges. Rather than standard academic subjects, the focus is on practical, often hygiene-related, education. The central conflict is not a villainous threat but the children's natural struggles with laziness, selfishness, and forgetfulness regarding basic manners. Unko-sensei creatively transforms these mundane struggles into humorous and memorable lessons about proper handwashing, the importance of friendship, sharing with others, and maintaining good health.

The main characters are centered on Unko-sensei himself, whose scatological form is never treated as gross but rather as an approachable and inherently funny figure for the children. His students are a varied cast representing common archetypes, allowing the young audience to see themselves in the classroom dynamics. The narrative is structured around short, self-contained episodes, each tackling a specific theme relevant to early childhood development. Notable arcs might include a week-long focus on cleanliness leading up to a school-wide germ inspection, or a series of lessons on emotional intelligence triggered by a dispute over a toy. The overarching narrative is not a continuous epic but the gradual, heartwarming growth of the class as they learn to navigate social rules and personal responsibility under the guidance of their most unusual, yet beloved, teacher. The stories are driven by simple, effective storytelling that prioritizes entertainment for a young audience while delivering clear, positive messages.