Female prisoner Zhenhui (Jin Yunzhen) gave birth to her son Min Yu in prison. Xiao Min Yu is like a little angel sent by God, making these women who have committed crimes like Zhenhui taste the warmth they have not seen for a long time within the fence. A condolence performance gave Zhenhui the idea of setting up a choir in prison, but Zhenhui was not only tone-deaf, but also had no relevant experience. Xiao Min-woo will be adopted 18 months later, and in order to get the chance to go out with her son before adoption, Zhenhui decided to stick to it no matter how difficult it is to form a glee club. With the help of many kind-hearted cellmates, the choir finally got together on a small scale, but Zhenhui did not expect that the day of going out with her son was also the day of parting with her son. The choir is like a big happy family. It not only brings joy to the prisoners who have lost their freedom, but also gradually mends the pain left in their hearts by the memory of suffering.