Shikishima Ritsu was living a fulfilling high school life.
Then one day, when Ritsu heard the new song from popular idol, μ, he noticed a cry for help hidding within the song.
Ritsu tried to confirm it with his friends, but none of them would respond to his questions, and they even acted off.
The suspicious incongruities continued piling up until the new year's entrance ceremonies. Yet the new students entering the school were-
Now afterward, even if the 
glass wall is removed,
،ثم بعد ذلك، حتى لو أزيل الجدار الزجاجي
Entfernt man danach die Glaswand,
Después, aunque quiten el cristal,
Después, aunque quiten el cristal,
Après ça,
même si on retire la vitre,
Ora, anche se il vetro venisse rimosso,
Depois disso, mesmo que
tire a parede de vidro,
Впоследствии, даже если стену уберут,