Imamura Seima is a sophomore in high school who spends his days in a village where the stars have disappeared from the night sky. One day, he meets a mysterious silver-haired girl named Plea Momobell. Plea happens to be a new student and upon joining Seima's class, she suddenly announces that she plans to revive the Starry Night Festival. And when Seima accidentally discovers the girl's "secret", he and his friends Eito and Chiyuri decide to help her...