During the 20th century, the world is undergoing a musical theater boom. Elite performers known as Dai Stars captivate audiences with their exceptional acting and singing. Among them, the most outstanding performers are awarded the title World Dai Star. Young and inexperienced Kokona Ootori dreams of being recognized as a World Dai Star. After several failures, she finally receives another opportunity to audition for the world-renowned theater troupe Sirius. Inspired by her best friend Shizuka, Kokona takes her first steps toward her goal and works diligently to improve her acting. However, the theater world is fiercely competitive, with many other girls vying for the spotlight—including Kathrina Griebel, a talented performer from Germany. To realize her dream, Kokona must earn the right to stand on stage above all else.