Haru Chitose, Eri Kumagai, Sarasa Ryuuouh, Kiri Mukae, Uori Mukae, Sasame Mitsukuri, Miku Nishio, Hiyo Yukino, Shupe Gushiken, Kotoko Kintoki, and Roro Morooka are the eleven members of "Music Girls," an idol group produced by Pine Records. However, they're a third-rate idol group that can't seem to sell CDs at all. But even though they're obscure and constantly in debt, the members and their producer, Ikehashi, are all trying their hardest. Ikehashi gets the idea that Music Girls needs a new member—an idol who can light a fire under them so that they can grasp success!
Yume Nijino aims to become a top idol, and she enrolls in the Yotsuboshi Gakuen (Four Stars Academy). This academy has a special group called the S4, who are the top four active idols in the school. Yume and the other first-year students aim to become a part of the S4.
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