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-
"My friend suddenly disappeared, 
but does anyone know anything?"
اختفى صديقي فجأة، لكن  "
"هل يعرف أحد شيئاً؟
Ein Freund ist plötzlich verschwunden,
hat jemand Informationen?
"Mi amigo desapareció de repente.
¿Alguien sabe algo?".
"Mi amigo desapareció de repente.
¿Alguien sabe algo?".
« J’ai un ami qui a disparu.
Quelqu’un a une piste ? »
"Un mio amico è sparito all'improvviso, 
qualcuno sa cosa può essere successo?"
"Um amigo meu sumiu de
repente, alguém sabe de algo?"
«Мой друг внезапно исчез, 
кто-нибудь что-то об этом знает?»