Dr. Fu Manchu has poisoned the renowned Dr. Hu Yan, who is to appear at a conference of the nations of the world, and replaced him with an impostor who will disrupt the conference's goal--a plan for world peace.
Dr. Fu Manchu kidnaps a renowned plastic surgeon, whom he plans to force to operate on Adolf Hitler--who is actually still alive and in hiding. Then Fu and Hitler will join forces to conquer the world.
In his search for a treasure of gold, Dr. Fu Manchu commits a brutal murder. Afterwards, he sends one of his assassins to finish off the only witness to the crime, who happens to be the victim's wife.
Dr. Fu Manchu has stolen a deadly collection of germ cultures from a laboratory in San Francisco, and plans to smuggle them through the port of Hong Kong.