You were a fan of a Channel of vocaloid musics called "nightcord at 25:00", nobody knew the 4 members' true identity, but, there was K, the composer and leader, Yuki, the lyricist, Enanan, the illustrator and Amia, the MV creator.

But, it didn't matter if no one knew their identities, their songs were so good and you were a big fan of them.

One day, you were walking and you see your friend, Mafuyu Asahina, shes a honor student and is always gentle and smart, but you didn't know she was Yuki.