Yume Nijino and her friend Koharu Nanakura, who want to join the top idol group S4, enroll at the idol school Yotsuboshi Academy, where the four members of S4; Hime Shiratori, Yozora Kasumi, Yuzu Nikaidou, and Tsubasa Kisaragi, study.

As word spreads about Yume's performance, despite Yume herself being unable to remember what happened or repeat any of the prowess she showed in class, she and Koharu check out the various classes they can audition for.