Robert Griffin (Jon Hall) escapes from an asylum and seeks out his old friends, Sir Jasper and Lady Irene (Lester Matthews, Gale Sondergaard). Griffin accuses the two of leaving him for dead in Africa years before and taking full claim for the diamond mine he had discovered, which subsequently made them rich. The two deny this and say they were told Griffin was dead by their guide. They offer to pay him half of what they have but Griffin, now quite insane, refuses and says he wants it all plus their daughter Julie (Evelyn Ankers)! They throw Griffin out, which leads to him meeting up with a Cockney blackmailer (Leon Errol) and eventually a scientist (John Carradine), who enlists him to take part in the inevitable invisibility experiment. The experiment is successful and Griffin, now invisible, returns to get even with Jasper and Irene.
Despite being named Griffin, this Invisible Man shares no history with the previous ones. It's John Carradine's scientist who has created the invisibility formula here. Also, Griffin is nuts before the movie begins so the invisibility formula can't be blamed for that. To make matters slightly more confusing, Hall plays the lead here and he also played the lead (another Griffin) in Invisible Agent.
The cast helps overcome a messy script. Hall is quite convincing as the psycho Invisible Man. Carradine, as usual, is great as the scientist. Leon Errol seems to ruffle quite a few feathers among viewers, judging by reviews here. His character was pretty much unnecessary but he didn't bother me. Gale Sondergaard is always a treat to watch but she gets little to do and seems to disappear from the story altogether after a half-hour or so. Lester Matthews is fine as the weakling husband who may or may not have left Griffin for dead in Africa. Evelyn Ankers has a thankless part. Halliwell Hobbes is the butler, as he often was in these films.
Part of the problem with the story is that no one is that likable. The closest thing to a hero in the movie is Alan Curtis' reporter character and there's something about him that kind of bugged me. Another problem is the script feels uneven, especially in the early part. Reportedly the first draft of the script had Jasper and Irene as much more villainous characters and no doubt was cast on their attempt to kill Griffin, both in Africa as well as upon his showing up at their house in this film. That's not the case in the final version yet the pair still seems unsympathetic, so I wonder why they bothered changing it all, if they did? The special effects are OK, if a little sloppy in some scenes. I think some reviewers have overstated just how sloppy they were. It's not like you see wires in every scene or even most scenes. I think only eagle-eyed viewers will spot most of the flaws with the effects.
Overall, it's a good movie of its type. Not great, but watchable B-grade entertainment. It's got a solid cast with a strong performance from Jon Hall in the lead. Still, it's easy to see why Universal stopped the series after this one.
