One day, Miu Takigawa suddenly receives a letter notifying her that she has been chosen as a member of brand-new project. Half in disbelief, she heads over to the location stated on the letter. There, she finds seven other girls summoned there in the same fashion. The girls behold a giant, top-secret facility. They stand in bewilderment as they are told they are going to debut for a major record label as an idol group. A new kind of idol, never-before-seen, is about to be born here.
Source: Official Site.
A Short series on the Official YouTube Channel of the group, titlled The Diary of Our Days.