Uzuki, Rin and Mio have been tapped to film the Cinderella Project's PR video. They go around filming their fellow members on a handy cam, a few of whom are challenging subjects. But after the video is done, the Producer makes an important announcement!

Miku Maekawa and Riina Tada are going to make their debut as the Cinderella Project's final unit. However, Miku aims to be a cute, cat-eared idol, while Riina's goal is to become a cool rock idol. The two are like oil and water, and both are strongly opposed to the unit idea. But when their participation in the units-only summer festival is on the line, they make an effort to get on the same wavelength, starting with becoming roommates!

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...