In 2032, the renowned idol group "7th Sisters" unexpectedly retired and vanished from the entertainment industry. This marked the end of the idol era until two years later when a young ambitious individual was appointed as the leader of Tokyo's next-generation idol studio, "777 (Three Seven)," commonly known as Nanastar. Despite this, the city continued to view idols as a relic of the past, and Nanastar faced similar struggles. However, one day, a captivating female manager appeared and stated, "If the idols of the past have disappeared, we must create new ones! True 'sisters' bound by strong connections!" Thus, the story of the future idol group, the Nanastar Sisters, began to unfold.
777☆SISTERS