In 1910, Hong Kong, under the rule of the British Empire, is a prosperous and bustling city, but, hidden in the shadows of its many narrow streets, the hideous members of the Red Dragon gang, a branch of the evil Chinese secret society of the Tongs, lurk and murder those who oppose to their tyranny, which thrives on vice, crime and the fear of the weakest.
A man who served prison time for intent to molest a child tries to build a new life with the help of a sympathetic psychiatrist.
A millionaire businessman's brain is kept alive after a fatal accident, and communicates clues to a doctor on the trail of the killer.
