Lai-fu, a farm boy from Mainland China, is hired as a killer and forced to enter into the hotbed of illicit businesses in Mongkok, one of the most densely populated areas in the world. Lai-fu meets Dandan, call girl from his home village by chance, and saves her from gangsters. Under flashy neon lights, they are chased by police and gangsters. Who will find them first, the lawful force or the lawless one?