Nyland Smith after sending Dr. Petrie and  Paul Sterling back into the underground laboratories of Dr. Fu Manchu contacts inspector Weymouth and asks him to broadcast Dr. Petrie's formulae 654 to Scotland Yard. After a close scrutiny of the beach and cliffs surrounding St Claire de la Roche, the insidious doctors stronghold, Smith and Weymouth prepare a raid. Weymouth returns the police launch where he instructs the wireless operator to broadcast the formula. Shortly after a cry is heard coming from the radio room. Upon entering they find the wireless operator murdered and Petrie's formula gone. Smith confronts Fu Manchu in his study, learns that Petrie's formula is now in Fu's hands and with the threat that Smith's life is forfeited Fu Manchu orders that Smith is taken away and prepares to abandon St Claire de la Roche...