The Mad Ghoul

Dr. Alfred Morris (George Zucco) is curious about the effects of an ancient nerve gas, used by the Mayans during rituals of human dissection to appease their gods. He takes medical student Ted Allison (David Bruce (actor)) under his wing to assist him with his experiments in using the gas on modern animals. However, despite Ted's enthusiasm for the success of their effort to revive Morris's dead monkey Choco (who was earlier exposed to the gas and died) by using a fluid from the heart of another creature, Ted also has on his mind his girlfriend Isabel Lewis (Evelyn Ankers), of whom Morris has also become enamored.