Shizu Miyanaga is a transfer student who moves from Kobe to an elementary school in Tokyo's Kiba district in 1956, following her father's job relocation. She arrives with prior training in piano and song, a background that sets her apart academically and musically from her new classmates and fuels her personal dream of becoming a singer.

Initially perceived as clever, she nonetheless faces the social challenge of being an outsider, which threatens to isolate her. Her musical proficiency becomes significant when the school, led by a passionate music teacher, begins preparing for a regional choir competition, and she becomes central to this effort.

Her story concludes when she dies in a marine accident. This event profoundly shocks her classmates, particularly Akira and Gon, and motivates the school to renew its efforts in the choir competition. Her memory acts as a driving force for the students and their teacher to persevere and dedicate their performance to her.