Driven by the ambition to one day reach the stars, humanity has colonized every planet in the solar system. This narrative follows young high school hopefuls and takes place in Fourth Tokyo, a Japanese prefecture on Mars. Iris Shirasaki is a third-year student and aspiring test pilot. Mizuki Sera is her classmate and mechanic, while Mizuki's brother, Kaito, serves as their homeroom teacher and the young director of the program cultivating their talents.