After School had already established itself as a popular group, known for admitting and "graduating" new members. After the news in mid-2011 that member Bekah would be "graduating" and ultimately leaving the group, After School announced their comeback for that following summer, promoting two subunit groups, simultaneously.

The 8-membered group was divided into two groups of four. After School Red had a sexy and powerful image, featuring the members Kahi, UEE, Nana, and Jung-ah. After School Blue on the other hand had a more sweet, innocent, feminine image featuring members Raina, Lizzy, Joo-yeon, and the then newest member Ee-young.

As soon as the teasers were released, in fact as soon as it was announced which members would be in which subunit group, the difference in styles were pretty clear. Both of the songs had a clear and definite difference in sound as well with After School Red's "In The Night Sky" having been produced by the Brave Brothers. It had a powerful beat with sexy dance moves. After School Blue on the other hand had a more soft and simple sound, channeling the style of Finkl from the late 90's in the song "Forever Love". Even more attention-grabbing was that a new group in the works, After School Boys, were the backup dancers.