Six Gravity (Gravi) and Procellarum (Procella), two idol units currently experiencing a dramatic rise in fame. On the day of Gravi and Procella’s handshake event, each of the members are waiting for the start of the event, doing as they individually please.

During that time, Shiwasu Kakeru, Kisaragi Koi, and Minaduki Rui meet Syunpei, a primary school student. Syunpei is taking the place of his sister, a fan of Kakeru’s, who had unfortunately come down with a cold.

Although Syunpei does not know anything about these idols……

One day, Rui caught sight of the "Tsukiusa." mascots (a familiar sight at the "Tsukino Dorms") walking. These "Tsukiusa."s were apparently looking for something important, so Rui decided to give them a helping hand.

Actually, these "Tsukiusa."s are also the members of the female idol units "Fluna" and "Seleas", who also belong to the same company. These girls, who originally were from the Moon Society, for some reason became "Tsukiusa."!

To be able to return to their original forms, Rui and the girls, embark on a strange and charming journey!