Stanley Ridges ("Prof. Kingsley") is seriously ill when Boris Karloff ("Dr. Sovac") performs a highly unethical operation to replace his brain with that of gangster "Red Cannon". Though successful in prolonging his friend's life, the newly invigorated Professor begins to demonstrate quite a few of the less savoury character flaws/traits of "Cannon". "Sovac" learns from one of these episodes that there is $500,000 hidden away somewhere, so he attempts to manipulate his friend to reveal the location of the loot. It's billed as a Karloff and Lugosi feature - but some recasting shenanigans meant th... read the rest.