In spite of Rumi Yokoi's utmost dedication to focus during class, she is easily sidetracked by the antics of her classmate, Toshinari Seki. As Yokoi diligently listens to the lecture, Seki keeps himself busy by building elaborate displays with an assortment of items, such as a complex domino arrangement or an intense shogi game. Despite her concerted efforts to stay on task, Yokoi cannot resist being entranced by Seki's peculiar pastimes, resulting in her receiving admonishments from their teacher. Nonetheless, due to Seki's spontaneous nature, attending class is always an intriguing experience.