John Agar stars as a scientist named Steve March who, along with his friend Dan goes to a mysterious mountain in the desert to check on some strange high level radiation.
March is the only one to return and he begins acting very odd. As it turns out his body has been inhabited by an evil brain named Gor from the planet Arous who wants to take over the entire universe. This causes trouble for his fiancee Sally, played by Joyce Meadows. She loves him and all, but Steve seems to have become a very cruel person who wants nothing but power, and Sally of course.
After blowing up several airplanes and killing more people a good brain named Vol comes to earth and takes over the body of Sally's dog George in order to spy and eventually capture Gor.
As you can tell, this is a ridiculous premise, but I still think this is an excellent example of the "anything goes" 50's sci-fi films. It's fun an entertaining and never takes itself too seriously. Suspend your disbelief and enjoy some good old fashioned fun.
The rest of the cast includes Robert Fuller as Dan, Thomas B. Henry, Dale Tate and Ken Terrill.