Sonya Rokoff acting as a representative of a European importing firm hires Victor Poten (Bela Lugosi), a Eurasian mad scientist who hates both whites and Asians, to ruin the tourist trade in San Francisco's Chinatown. Rokoff soon realizes that Poten has become an unstoppable monster, beyond her control. Poten's nefarious activities draw the attention of newspaper reporter Joan Whiting and her novelist boyfriend Martin Andrews who begin to investigate the mysterious, and violent events in Chinatown.

Sonya Rokoff acting as a representative of a European importing firm hires Victor Poten (Bela Lugosi), a Eurasian mad scientist who hates both whites and Asians, to ruin the tourist trade in San Francisco's Chinatown. Rokoff soon realizes that Poten has become an unstoppable monster, beyond her control. Poten's nefarious activities draw the attention of newspaper reporter Joan Whiting and her novelist boyfriend Martin Andrews who begin to investigate the mysterious, and violent events in Chinatown.

Captain Matthews (John Elliot) is paid 40,000 dollars in cash by Nick Conrad (Bryant Washburn, who also played an attorney in 'Prison Mutiny') for his shipment of silk from China. About 15 seconds after he gets the cash, he's lured away on a false pretence and robbed by Conrad's henchmen. Newspaper reporter Jerry Mason (Lawrence Gray) witnesses the robbery and steals the cash from Conrad. Conrad's thugs (all of whom have mustaches and crisp suits) chase him into his friend Fred Klein (Fuzzy Knight)'s delicatessen. The two of them get taken back to Conrad and forced to talk.