Dr. Mabuse, the nefarious supercriminal who regularly confounds the authorities with his ill-conceived and far-fetched world domination schemes, is ready to do battle once more with the forces of good. This time he's after a invisibility gizmo invented by a disfigured scientist seeking to hide his ugliness. One time Tarzan, Lex Barker, plays Mabuse's nemesis--FBI Agent Joe Como. The scientist likes to hang out at a theater where he can spy on the actress of his dreams. Apparently, he thought that by making himself invisible she wouldn't be frightened of him. Evidently, it never occurred to him that moving things around and touching her while he's invisible might frighten her. Is this guy a loser or what?
Eventually, Mabuse gets his evil hands on the device and creates a small army of transparent thugs. The plan is for them to wreak havoc and plunge the world into chaos. It's up to Joe Como and his band of incompetent German cops to thwart the scheme.
The writing for this film is incredibly bad. For example, since when did the FBI's jurisdiction extend to Germany? How did Mabuse know about the invisible man's obsession for the actress? In fact, how did Mabuse know there was an invisibility gadget? I also don't know how the scientist knew that Mabuse knew. Since the scientist was invisible why didn't he use that advantage to locate Mabuse and thwart his plans? Or better yet, since he allegedly cared so much for the actress why didn't he just make another device for her? She could then become invisible if Mabuse's goons threatened her? In my opinion, Dr. Mabuse isn't half as crazy as the folks who produced this turkey.