In 2032 the legendary idol unit 7th Sisters abruptly retires, and the idol business collapses into a long slump. Two years later, the twelve-member group 777☆SISTERS performs out of the next-generation studio 777, known as Nanastar, and is partly managed by Coney Rokusaki, a former 7th Sisters member. They find some success, but nothing close to the stars of the past. When equipment trouble threatens one of their concerts, Hakkaku Kouzou, who runs the once-dominant studio HAKKAKU, steps in to help. The girls then learn that HAKKAKU, the hall behind many of 7th Sisters' most famous shows, faces closure after a takeover by Namekawa Concern. Its funding will continue only if the seats are filled, so they set out to perform there and save it.