时已入夏，制作人与偶像的距离也确实地缩短了，整个企划的气氛良好。而这一次兰子将以独唱CD出道！但兰子所想象的形象与制作人所看到的兰子的形象有很大的差异……。制作人希望理解兰子，兰子则希望将自己的形象传达给制作人而努力，但——。

夏Fes终于要正式迎来了。成员们对于企划全员参加的大舞台感到紧张，不过以美波为中心，大家顺利地进行了排练。此时，美波由于极度的紧张状态而倒下。LOVE LAIKA急忙让兰子加入来代替，总算是让灰姑娘企划的舞台能继续进行，然而在突如其来的豪雨袭击之下，演唱会中断了……！

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...