Mizuki Haruno, who has been spending her days feeling blue, was taken to a live concert by her childhood friend, Nozomi. She caught a glimpse of the "exciting world there." The story of Mizuki who became a high-school student begins now! This is a rockin' youth story woven by the four individual girls from the music band at Hakumai High School in a town in Hokkaido!

The story is set in the future where humanity and the Z/X have entered a treaty and headed towards a moment of peace. Azumi Kagamihara—a girl affiliated with the Blue World—is chosen together with her Partner Z/X Rigel to enroll in Fujimisaki Academy, a school established to gather girls that are partnered with Z/X from all over Japan.