On the Suzhou River in Shanghai, Ma Da (Jia Hongsheng), who delivers goods on a motorcycle, takes on the job of picking up the innocent girl Mudan (Zhou Xun). As they get along, Mudan falls in love with Ma Da, but just when she decides to commit her life to him, Ma Da, obsessed with money, joins his gangster friends to kidnap her, leaving Mudan disheartened and jumping into the Suzhou River. Before jumping, Mudan says that she will turn into a mermaid and look for Ma Da again. Five years later, Ma Da, who regrets his actions, suspects that Mudan has returned and starts looking for her. When he sees Mei Mei (Zhou Xun) performing as a mermaid in a bar, Ma Da believes that she is Mudan, but Mei Mei is just another infatuated woman.