Directed by Stephen Chow, The Mermaid follows property tycoon Liu Xuan (Deng Chao) as he purchases the Green Gulf, a coastal wildlife reserve. Liu Xuan plans to turns the reserve into a land reclamation project, and uses sonar technology to get rid of the sea life in the area.
What Liu Xuan does not know is that Green Gulf is the home of merpeople and the sonar (in addition to heavy pollution) has caused many of them to die or get sick. The few survivors live in an abandoned shipwreck in the gulf, and plan to assassinate Xuan for his deeds.
The merfolk send Shan (Lin Yun), a beautiful young mermaid, who has been trained to walk and dance on her fins and hide among humans, to seduce and assassinate Xuan.
What could go wrong?