Dr. Sartorius (Boris Karloff) is without financial means to experiment for a paralysis cure and must give up his lab work. He meets Lady Yvonne Clifford (Mona Goya), a very wealthy wife of an ailing cotton millionaire Sir Charles Clifford (Morton Selten). Lady Clifford asks Dr. Sartorius to help her obtain her husband's money. Dr Sartorius eager to obtain money for his expenses and laboratory studies, agrees to poison her husband, making it look like he died from natural causes. After a period of time, Sir Charles begins to suspect Dr. Sartorius of making him gravely ill. This Karloff movie has a very different ending which surprised me. Karloff is without any monster makeup, however, he is terrifying and proves to be a very evil French doctor as usual.