Scientist working frantically in seclusion finds a way to locate the impact crater of a meteor carrying a new radioactive element. All (pseudo)science and breakthrough technology talks of the 1930s are right there, including the idea that radioactivity could heal any illness if properly harnessed. When he summons his rivals -who had cast him out of the scientific community and ridiculed him - to witness his discovery, they propose a 'joint' expedition to Africa...of course they end up stealing much of dr. Rukh's original discovery, giving him only residual credit. In addition to that, an effeminate weakling who looks like a supporting comedy actor from the worst Abbot&Costello (Lawton) literally steals dr. Rukh's young trophy wife (Drake), who falls head over heels for that scrap of a human being. Having grown horns like a deer wasn't going to make dr. Rukh (Karloff) any friendlier, so he embarks in an undercover revenge mission...killing 2 of his foes and friendly dr. Benet (Lugosi), the only one who had helped him...finally succumbing to the deadly radiations that had allowed him to embark in his revenge to start with but ( to my utmost dissatisfaction ) sparing the adulteress and that poor excuse for a human being she had married. Acting is mostly fine, with Karloff & Lugosi being very good. Check the hysterical chambermaid scene... Other characters aren't worth mentioning... Recommended, much like ALL old Universal horrors...