As the Invisible Dr. Mabuse title appears on screen, we see an invisible man holding up opera glasses behind the lettering. It’s a neat trick, as the phantom is not Dr. Mabuse.
This 1962 movie follows the formula of Return of Dr. Mabuse in building the story around an SF McGuffin that will give Mabuse power absolute. It’s not a patch on the previous films in the series, but it is entertaining. That cannot be said for its sequels.
The invisible man is holding opera glasses because he’s watching an operetta, The Dancer, the Executioner and the Clown starring the lovely Liane Martin (Karin Dor). Although he’s sitting in an uncurtained box seat, nobody seems to notice the floating glasses. Cut to FBI agent Prado (Alain Dijon) snooping around backstage, where the clown from the operetta captures and interrogates him about … Operation X! Too bad the clown plays rough; he injures Prado badly enough it’s obvious the agent can hold out until he dies. A disgruntled, off-screen Mabuse (voiced by Wolfgang Preiss) shoots Prado to wrap things up.
The backstage crew stuff the G-Man into a steamer trunk and take him to the docks. They don’t deep-six the corpse immediately, so the cops wind up discovering the body. Mabuse, seen as a shadow on the wall, warns them not to fail him again (keeping Mabuse off-screen presumably let people assume he was invisible).
Joe Como (Lex Barker) from Return arrives to investigate Prado’s death. Commissioner Brahm (Siegfried Lowitz) tells him Operation X is an underworld scheme to secure a superweapon “more important in its possibilities than the super-bomb and space rockets.” Although Brahm sees the resemblance to Mabuse’s ambitious schemes, he’s certain the doctor is dead. Como gets a warning message that proves otherwise, but Brahm scoffs; the commissioner’s refusal to trust his instincts drives Como up the wall.
Meanwhile the invisible man shadows Liane, kisses her while she sleeps and warns Como to stay away from her. Initially skeptical, Como realizes Liane’s not imagining a phantom stalker. Then he learns the secret super-weapon Mabuse wants is, as you’ve probably guessed, an invisibility treatment created by Professor Erasmus (Rudolf Fernau). Erasmus’ assistant Bordoff (Kurt Pieritz) regurgitates the pseudoscience behind it (why bother? I can’t imagine anyone watching this would have science objections) and tells Como the professor hasn’t left his impregnable, high-security laboratory in forever. All his messages to Bordoff come over the phone. Hmm — has Mabuse already replaced Erasmus?
Actually no (as David Kalat points out, most of Como’s theories are wrong). Erasmus, scarred in a lab accident, is pulling a Phantom of the Opera and watching over Liane, whom he thinks he loves. That love does not, however, stop him driving Liane crazy with fear of her unseen stalker. Liane’s doctor, Krone (a bearded Preiss), sends the terrified woman to an isolated hotel to rest. Oh, wait, it’s really to brainwash her, then return her to Mabuse’s lair under the theater. Mabuse offers Liane to Erasmus in return for the invisibility ray. Erasmus has the decency to refuse, but folds when Mabuse threatens Liane’s life. The professor gives Bordoff instructions on entering the lab to remove the ray, but also tells him how to sabotage the equipment. Too bad that Bardoff is actually Mabuse.
Just to cover his bases, Mabuse has Liane drug Como; when that fails, he has his men capture the G-man with brute force. Como breaks out (a good action sequence) but Mabuse now has an invisible army, ready to blow up a visiting American official’s plane. Brahm counters with classic low-tech solutions, such as trip wires to detect the phantoms and water cannon to make them visible. The attack is an embarrassing failure.
Mabuse retreats to Erasmus’ lab where he finds Krone (surprisingly Krone is not Mabuse, just a henchman) and kills him for his failures. What a shame Krone already reset the lab’s security; Mabuse can’t get back out, and the lab’s now on fire. The cops manage to save Mabuse’s life, but not his mind. Off he goes to a mental hospital for the upcoming remake of Testament of Dr. Mabuse. Como gets Liane as his reward.
Testament of Dr. Mabuse this ain’t, but it’s an entertaining quickie thriller. Barker’s Como is one of the series’ better men of action and Dor (best known as SPECTRE’s Number 11 in You Only Live Twice) gives a good and sexy performance. But if you decided to stop the series with Return of Dr. Mabuse you wouldn’t be missing much.