In the1930s, Xiaoyun (Zhao) and Xiaohong (Zhou Xuan) were tricked into Shanghai and sold to piano players and pimps in Shanghai brothels. Xiaoyun was forced into prostitution. Xiaohong was still young and had a good voice, so she followed the pianist to the teahouse to sing all day. The two sisters live in slums. Opposite them, there lived Lao Wang, a newspaper vendor, and Chen Shaoping, a drummer (Zhao Dan). Because Chen Shaoping often plays with Xiaohong in front of the window when he is free, they gradually develop feelings for each other.

Xiaohong was pestered by hooligans while singing, and the other party wanted to bully her as a concubine. Xiaohong asked Chen Shaoping to discuss countermeasures. They want to use lawyers to do justice, and they don't want lawyers to only recognize money. In desperation, they had to run away. In this process, Lao Wang felt pity for Xiaoyun, but Xiaoyun dared not face it because of his inferiority. The pianist happened to know the whereabouts of Xiaohong and let Gu know. When Gu arrived at Xiaohong's residence, there were only her and Xiaoyun in the room, and her life was dying.

The drummer in the band is clever and humorous. He and two of his kind, Xiaohong, often express their feelings by singing and playing the piano. Xiao Yun has a crush on him, but he looks down on her because of her. Later, with the help of his brothers, he secretly took Xiaohong out and married Xiaohong. ?