Mother Mouse arrives during the fourth nightly visit to the protagonist's residence, accompanied by her visibly ill child. She urgently seeks help, explaining her conviction that the sound of the cellist's music holds healing power, having cured other ailing animals nearby. When initially told the cellist lacks medical expertise and cannot assist, she persists, emphasizing her belief in the therapeutic effect of his playing.

Following her request, the cellist places the sick young mouse inside his instrument's sound hole and performs an improvised rhapsody. After the music concludes, the young mouse recovers fully, demonstrating renewed vitality through active movement. Mother Mouse expresses profound relief and gratitude with visible emotion, shedding tears of thanks before departing with her healed offspring. Her interaction showcases unwavering maternal dedication and belief in music's transformative capacity.