Kashiwagi is a stunningly beautiful, self-described NEET part-time teacher who went to a music college in Tokyo. Her old middle-school classmate Matsuyama is now the advisor for a middle school chorus club on Nagasaki Prefecture's Gotō Islands, but she has to go on maternity leave. Matsuyama asks Kashiwagi to take over the club for one year. The chorus club had only female members before, but the arrival of Kashiwagi suddenly attracts lots of boys, resulting in conflict among its ranks. Despite this, the club prepares for NCon, NHK's real-life nationwide school music competition, with its newly diverse roster.