Bland former child actor Johnny Downs earns top billing in this low-budget horror film, but the real star is that most psychotic of all the mad doctors George Zucco. The British-born character actor plays Dr. Lorenzo Cameron, a discredited -- and quite mad -- medico who has discovered a way to turn his helper, Pietro (Glenn Strange), into a wolf man. The lycanthropic experiments succeed only too well and although Dr. Cameron spouts plans of turning his discovery into a weapon in defense of the civilized world ("men who are governed by one collective thought, the animal lust to kill without regard for personal safety! Such an army will sweep everything before it," Dr. Cameron promises), he instead unleashes his creation on those fellow scientists who had engineered his ouster from academia in the first place. Before long, however, the good doctor is unable to control the wolf man, who threatens to kill everything in his past, and only newspaper reporter Tom Gregory (Johnny Downs) and Lenora (Anne Nagel), Cameron's innocent daughter, may be able to stop the monster. A perennial cult favorite, The Mad Monster was released on the heels of The Wolf Man (1941), but cost a fraction of Universal's elaborate lycanthropic exercise.