卯月、凛、未央参加了灰姑娘企划宣传影片的拍摄。她们拿着相机来回对成员们进行拍摄，但个性各异的成员们却很难搞定……。摄影结束后，制作人向成员们宣告了重大发表！

Miku and Riina are concerned with improving as a unit to get ready for “Cinderella’s Ball,” despite their usual clashes over the direction of the unit. Meanwhile, Riina becomes friends with a rock idol she admires, Natsuki Kimura, whom Executive Director Mishiro has invited to join a new rock-idol unit.

Connecting with Natsuki, who is devoted to rock, makes Riina remember how much she loves it too. Riina is torn over what she wants to do. Miku picks up on the fact that Riina isn’t her usual self and worries about her partner, but decides to wait until she is ready to talk...