In the 20th century, the world is experiencing a musical theater boom. Top performers known as Dai Stars enthrall the audience with their marvelous acting and singing. Among them, the greatest performers are given the title World Dai Star.

Young and inexperienced Kokona Ootori dreams of being recognized as a World Dai Star. After multiple failures, she finally gets another chance to audition for the world-renowned theater troupe Sirius. Inspired by her best friend Shizuka, Kokona takes the first steps toward her goal and works hard to improve her acting. However, the world of theater is fiercely competitive, as many other girls seek the spotlight—including Kathrina Griebel, a talented performer from Germany. In order to fulfill her dream, Kokona needs to earn the right to stand on stage above all else.