Spoiler alert! I saw this serial years ago on a kid's TV show when I was 8-10 years old. It has to this day been one of my favorite serials of all time. Bela Lugosi is great as the mad Dr. Zorka. The evil-looking robot, the invisibility belt, the plot for world domination, etc. are all here in this 12 part serial. Some of the cliffhangers are nicely done, my favorite being the airplane crash that occurs in the 1st-2nd chapters. When I watched this serial again after getting a DVD-R from Amazon it brought back some wonderful old memories. I remember watching the episodes with my maternal grandmother (the person who got me started on science fiction and horror movies). So, get some popcorn, set back and enjoy a gem from the old days!!