In the futuristic setting of 2035, Manabi Straight! revolves around the daily lives of a spirited group of high school girls at the dwindling Seioh Private High School. With a declining birth rate leading to school closures and a pervasive sense of low morale, Seioh faces similar challenges. The narrative kicks off with Manami Amamiya's arrival at Seioh, marked by playful mishaps involving a futuristic scooter and a swim competition, culminating in a heartening school anthem performance that earns her the role of student council president. As Manami collaborates with Mika Inamori, the sole other council member, as well as classmates Mutsuki Uehara, Mei Etoh, and Momoha Odori, the focus shifts to their student council duties. Through refurbishing the council room, Manami and her companions embark on organizing the upcoming student festival, navigating the tasks and trials that lie ahead.