Hizuru teaches elementary school in the story's rural town, commanding deep respect and admiration from her students. They see her as their ideal of adult femininity, especially the girls in her class, who develop a strong affection for her and affectionately name their pet goldfish after her. Beyond teaching, Hizuru provides key historical context about the area's ancient Heian-period capital, aiding the main characters, Shinko and Kiiko, in connecting their imaginative explorations to local history.

News of Hizuru's impending marriage directly motivates the children to build a special pond for their goldfish, symbolizing their emotional investment in her happiness. However, this marriage necessitates her departure from the town, marking a narrative transition where the children confront adult realities affecting their lives. Before leaving, subtle hints about her personal life emerge when she is seen burning letters, suggesting complexities in her history prior to the marriage. Her departure represents one of the children's early experiences with the impermanence of relationships and the progression into adulthood.