Toru Ariga, a first-year high school student and member of the school newspaper club, one day notices that when his classmate, Natsumi Higurashi, takes off her glasses, she looks exactly like the super idol MEAN. Ariga immediately begins investigating her background, but he also has a reason to want to know about her beyond his role in the school newspaper club.

One evening, as Ariga was walking home, Natsumi left him with a mysterious message. Determined to find out the truth, Ariga went to the dressing room after MEAN's concert and witnessed the Knockers transforming into monstrous forms. When he rushed to report the situation, Natsumi appeared before him, accompanied by Yamane and still wearing MEAN's costume. In front of Ariga's eyes, she spread her large wings, defeated her enemies with a sword created by her mysterious singing voice, and then told Ariga that she only had one year left to live.