When Cyan inadvertently enters the realm of Midi City through a rhythm game, she discovers a world where music holds immense power. As she learns about the city's musical hierarchy and the looming threat of darkness, her own musical prowess and inner strength come to light. Despite her self-perceived ordinariness, Cyan possesses extraordinary guitar skills and a hidden ability to combat evil through her enchanting music. Together with Chuchu, Retoree, and Moa, Cyan embarks on a musical journey where talent, friendship, and courage intertwine to shape the fate of Midi City.