Akihito and his sister Umi make their way to a once all-female academy that is preparing to welcome its first male students amid concerns over dwindling birth rates. The siblings settle into this evolving environment, which faces the threat of closure in the near future. As they begin classes and daily routines, Akihito and Umi encounter the nuances of life at the institution. Their early days set the stage for deeper relationships and unexpected situations ahead.
