Gale Sondergaard was terribly misused by Universal Studio's. She had a great talent but was wasted in grade Z film's such as this tripe. Two years before she had made a big impression as one Sherlock Holmes most diabolical and resourceful adversaries in "The Spider Woman" 1944. She and Basil Rathbone were wonderful as they tried to one up each other right to the end. This movie promised to be a return of that original character. But that wasn't the case.It's a mystery with more plot holes the you could imagine with a story line that makes very little sense.
Brenda Joyce is the damsel in distress, and Kirby Grant is her rescuer and hero of the story. Grant went on to play Sky King a decade later. Rondo Hatton is around to be sinister but is just sort of "there".
You can figure out what's going on fairly quickly. The question becomes WHY is it going on. When that WHY is reveled at the end of the film it's totally unsatisfying. If you are are a Sondergaard fan you will like the way she gives it her all to keep things going. She's the only reason to watch this picture. Beyond that there really isn't anything to recommend The Spider Woman Strikes Back.