Ichika Orimura begins to attend the Infinite Stratos (IS) Academy. As the only male in the world to pilot an IS, he becomes an instant sensation among the all-female students of the academy. With his homeroom teacher being his older sister and champion IS pilot Chifuyu Orimura, assisted by substitute instructor Maya Yamada, Ichika is uneasy and unprepared as he tries to get used to the academy. He later learns that his dorm roommate is his childhood friend, kendo champion Houki Shinonono, whom he has not seen in six years. When his class decides to elect him as their class representative, Cecilia Alcott, a British IS pilot, objects and challenges him to a duel for the position.