Seiji Matsuoka, a flamboyant student at Higashi High School and art club member, sports a distinctive Beatles-inspired mushroom cut reflecting his passion for pop and rock music. His driving ambition is to become a successful singer to financially support his family. To this end, he forms the band "Olympus" and actively recruits Sentarō Kawabuchi as their drummer for the school festival, sparking initial tension due to Sentarō's dedication to jazz. Sentarō eventually agrees after learning of Seiji's family circumstances. Technical issues with the band's amplifiers during their festival performance inadvertently lead to an impromptu jazz session between Kaoru Nishimi and Sentarō, diverting significant audience attention away from Seiji's band. Later, Seiji reconnects by challenging Kaoru and Sentarō to perform at another festival, temporarily joining their ensemble as a vocalist alongside Ritsuko Mukae and Tsutomu Mukae for the collaborative event. His interactions often highlight cultural contrasts between pop/rock and jazz, while his persistent pursuit of musical success underscores his commitment to his family.