Tsubame is a 14-year-old girl. She has a crush on university student Toru, who lives in the same neighborhood. Tsubame lives in a warm environment with her father Toshio and stepmother Asako, but, one day, she learns that Asako is pregnant. She feels left out because of her stepmother's pregnancy and she also feels frustrated because she can't reveal her love to Toru. The rooftop of her calligraphy class is the only place where Tsubame can find solace. There, she feels the wind and looks up at the stars. One night, Tsubame goes on the rooftop as usual. She finds a strange kickboard scooter and a mysterious old woman Hoshi-baa appears in front of her.