A stowaway cuts his way out of some packaging unloaded at the London docks and later buys himself some new clothes, paranoid about being spied on all the while and hiding from any nearby policemen. When the clothes merchant inspects those he left behind, he finds a newspaper in the coat pocket with a front page story of how the man, Robert Griffin, escaped from a mental institution in Cape Town, South Africa, committing triple-homicide in the process. Griffin heads to the luxurious residence of the Herrick family, meeting up with Sir Jasper and Lady Irene, whom he was friends with five years before, the three of them having embarked on an African safari. The couple are stunned to see him, as they were told he'd died from injuries he sustained during the trip, but Griffin accuses them of leaving him behind after something hit him on the head and knocked him unconscious. He says that another hit on the head a couple of months before brought his memory back and now, he's returned to get his share of the diamond fields they discovered on the safari, as per an agreement they made at the time. Telling him that all of that money was lost in some bad investments, they instead offer Griffin half or more of their own money but he says he wants it all and doesn't care if it'll ruin them. He also wants their daughter, Julie, who's currently dating Mark Foster, a London journalist. Fortunately for them, Griffin passes out from the drink they served him and, realizing how their former friend has completely lost his mind, send him out of the house after taking away his written agreement, hoping he'll get help for his unhinged mental state. Griffin warns them that they can't get rid of him so easily and, after unsuccessfully attempting to sue them through the help of Herbert Higgins, a cobbler who saved him from drowning after he was thrown out, he later stumbles across the house of Dr. Peter Drury, a scientist whom he learns has come up with a serum for invisibility. Realizing the potential of it, Griffin allows the eager scientist to use him as his first human subject. The experiment works and Drury prepares to make his triumph known to the scientific world but Griffin has no intention of helping him become famous, as he leaves to settle the score with the Herricks. He forces Sir Jasper to sign their entire estate over to him, frightens Lady Irene into a delirious state, and it seems like now, nothing can stop him. Even worse, in order to have Julie, he has to become visible again through a total transfusion of someone else's blood and he doesn't care whom he has to kill in order to make it happen.
Yet again, we have a film whose title makes you anticipate the resurrection of Jack Griffin and, indeed, Universal was hoping that Claude Rains would return for this one but that ended up not happening. Instead, they went with Jon Hall, who was no stranger to the invisibility gimmick, having starred two years earlier in the wartime spy thriller, Invisible Agent. The characters he plays in these two films couldn't be more different from each other, as one was a reluctant but ultimately heroic secret agent, while the title character here is nothing less than a complete madman. Jack Griffin may have been a homicidal maniac as well in the original film but, aside from Rains' wonderfully theatrical performance, the filmmakers at least got across the notion that he was really a decent guy whose naivety and overzealousness led to his horrific change. It's implied here too that Robert Griffin (who's not related to Jack or The Invisible Man Returns' Frank in any way) was a good guy when a couple of blows to the head caused him to go insane but we never get a single glimpse of that now los good person. Instead, all we see is a deranged, greedy psychotic who murdered his way out of a mental institution in South Africa and has arrived in London to ruin the lives of a family whom he feels has cheated him out of a fortune. He wants his half of the diamond fields they discovered on their African safari and when he's told that the money from it has been lost in some bad investments and is offered a big portion of their own money, he tells them he wants everything, including their estate snarling, "Who cares?" when he's told that such a demand would ruin them. He even threatens to take them to court over their "attempted murder" of him if they don't cooperate and also has his eye on their daughter, Julie, whose photograph he's kept since the safari. When he becomes drunk and hardly able to function, they throw him out of the house but that doesn't deter him one bit. He tries to use a scheming, poor cobbler named Higgins to sue the Herricks and when that doesn't work, he comes across Dr. Drury and his invisibility formula and, realizing the potential of it when Drury tells him of how his dog, Brutus, was able to use it against other dogs who'd ganged up on him before, agrees to become his first human test subject, feeling he has nothing to lose even if he does die from it. When it works, Griffin becomes more emboldened than ever, heading back to the Herrick estate, forcing Sir Jasper to sign over the entire estate, all the while reveling in the fear and sense of helplessness he's causing, frightening Irene into a near catatonic state, and bullying his way into Higgins' shack, forcing him to let him live there. The only halfway decent thing he does is help Higgins win at darts so he can get money to pay his rent with and even then, he's only doing it to ensure that he'd have a place to stay as well.
There are a couple of other noteworthy characters, including Cleghorn (Halliwell Hobbes), the Herricks' faithful butler, whose having witnessed Robert Griffin leaving on his own two feet when they pushed him out the door, instead of being nearly drowned intentionally by the couple, tips Jim Feeney, (Ian Wolfe), the lawyer, that Griffin's claims were pure lies. He and Mark Foster are also unknowingly very nearly killed by the Invisible Man when he tells Foster of Griffin's visit to the Herricks, which creates a connection between him and Lady Irene's frightened ravings, and is forced to go along with Griffin's alias of Martin Field when he forces them to let him stay at the house. The other noteworthy role is that of Sir Frederick Travers (Leyland Hodgson), the chief constable and friend to the Herrick family. He doesn't have much screentime except near the beginning and at the end but I find him memorable for his rather theatrical way of speaking, such as when he says, "We've nothing more to fear from the Invisible Man. He's dead," and the film's final line where he has this to say about Griffin, "Warped by imaginary wrongs. A man fighting shadows. He's to be pitied, really. He probed too deeply in forbidden places. What a man earns, he gets. Nature has a strange way of paying him back in his own coin." Nice line, but it doesn't make me pity Griffin any. Also, Skelton Knaggs, a character actor of the times who had a very creepy-looking face, appears briefly as a man who tells Travers that he picked up a man near the scene of Drury's murder and dropped him off at the Herrick home, leading to the constables discovery of Griffin's being the Invisible Man.
Of the three actual Invisible Man films (that is, discounting The Invisible Woman, Invisible Agent, and Abbot and Costello Meet the Invisible Man), I'd say that this is the lesser of the bunch for a couple of reasons. One, it's the most dead serious, with little of the humor in its predecessors, since this Invisible Man is a true psychopath whose only use of his newfound ability is to threaten and kill rather than mess around with people, often laughing evilly at the terror he sees befall them. Other than the scene at the inn, where Griffin helps Herbert Higgins win a game of darts, there's very little funny about this film. In addition, this film has always felt less sophisticated and more like a B-movie than The Invisible Man and The Invisible Man Returns, probably because you don't have the sequences of people forced to rely on intelligence and ingenuity in order to find and catch someone that they can't see. Also, the science of invisibility isn't treated as well as it was before. Yeah, The Invisible Man Returns may not have added anything new to what we were told about the serum's nature in the original but it least still used the same serum, whereas here we don't get much of any information of how Dr. Drury came up with the formula except for vague explanations of how things are visible to begin with, which may or may not still hold up today. And it uses the gimmick of blood transfusions somehow being a cure for invisibility that was introduced in the second movie to a larger extent, to the point where Robert Griffin becomes something of a vampire in order to retain his invisibility. I'm not one who gets hung up on nitpicks and whether or not something is scientifically plausible so long as I'm entertained but I still find it a little bit sad to see how this initially intelligent series of films kind of degenerated. It's still better than some other films Universal made around this time, such as those latter "Kharis" Mummy movies (and yes, I know I keep harping on them, but those movies were so ungodly lazy).
At this point, John P. Fulton must've had his invisibility effects down to a science, as he continued to use the same techniques of black velvet bodysuits, matting and compositing work, and wires and they still look pretty good. Like before, you can still see the outlines of the actor's matted out head and limbs in certain shots, especially in the scene at Herbert Higgins' house where Robert Griffin puts some flour on his face in order to make it visible for him, and the effects have the same, odd filtering aspect that they always have but, again, for the time, it's still impressive stuff. One of the most startling images Fulton was able to pull off was when Griffin puts water on his face in order to frighten Lady Irene, which looks pretty eerie when you see it in close-up, and another is the transparent head behind the bandages when Griffin reveals his condition to Higgins. He was also able to gradually fade out Hall's head for the scene at the Herrick house where he realizes he's turning invisible again and runs off in a panic and while there are some oddities to the effect, namely how overly pale Hall's face looks when this starts, being able to do that while the actor was moving was quite an accomplishment for the time. Fulton built upon the effects of invisible animals that he'd done before in The Invisible Man Returns, this time by having a harness move around by itself and even turn over on its side as if a large, invisible dog were wearing it. The part where Dr. Drury feeds the invisible Brutus and you see the food disappear in mid-air looks particularly good and it's hard to tell exactly how they did it. As for the wirework, it's still a little bit tricky and plainly obvious in certain shots, particularly when Griffin lifts an unconscious Mark Foster up onto a table in order to drain his blood, an error that was pointed in the Now You See Him documentary, and the scene with the throwing darts do look more like they're traveling on wires rather than carried by invisible hands but it's not that big of a deal. One effect that I can't figure out is when Griffin is casually tossing a knife up into the air and then catching it by the handle as he tells Sir Jasper what to write while forcing him to sign over everything to him. I assumed it was just a matted out Hall tossing and catching it but I thought I saw strings on it at some point, not counting when it's floating around in a horizontal position. That kind of motion would be really hard to do with strings, so I'm not quite sure. Maybe it's really simple but it had me stumped when I was looking at it.
Another memorable, and more humorous, scene takes place shortly afterward at the Running Nag Inn. There's a bit of humor early on when Herbert Higgins walks through the door, not knowing that the completely invisible Griffin is behind him and closes the door on him, prompting him to fling it open again into his back. After a couple of moments where Higgins is tempted by rumors floating around the bar about an invisible man to tell the truth and Griffin makes his contempt for Mark Foster known by knocking over his drink and telling him Julie isn't for him, he ropes Higgins into a game of darts with a much more skilled man, Neddy, challenging him out loud so everyone thinks Higgins was the one who said it. After some stalling, Higgins is pressed by Griffin into taking up the challenge, with the Invisible Man making a large bet as well. Once the bets are placed, Griffin tells Higgins to just go through the motions of throwing and he'll take care of everything else. The game starts and Higgins holds up one dart and just barely motions his hands when the dart suddenly glides out of it, straight into the bulls-eye on the dartboard. Neddy writes it off as just bull luck and Higgins then makes like he's going to throw it behind him, between his legs... when nothing happens. After a few seconds, Griffin tells him to give him time to get back to where he stands after running with the dart and sticking it in the board. Higgins then boasts that the next move is his special "delayed dart" and goes back into the motion of throwing it through his legs, the dart this time gliding through the air and hitting another bulls-eye. Higgins' "skills" start attracting quite a crowd as he boasts he doesn't even have to look and motions his arm around the back of his head and motions, with the dart again traveling perfectly towards the bulls-eye. Neddy accuses him of cheating and takes a closer look at the darts but once it's clear that there's nothing special about them, Higgins tries to talk him into betting another five quid but Neddy, obviously nervous, says he's satisfied with the five he knows he's going to win. Higgins, after adding, "You hope," takes one man's accordion and has another place a dart on top of it. He then presses the instrument and the dart flies through the air gracefully and hits the bulls-eye. After playing the accordion in celebration, Higgins tosses the rest of the darts to Neddy, as it's his throw, when Griffin sticks them all in the bulls-eye, much to everyone's astonishment. Neddy refuses to compete against that, making it Higgins' win, but when he tries to leave, Neddy, being a sore loser, runs up to him, swings him around, and demands his money back. Neddy yanks it out of his hand but when Griffin growls, "Ya thievin' braggart!", he prepares to knock Higgins' head in for the insult. However, a punch from Griffin sends him sailing across the room and he tells Higgins to take his money back from him, which he does. Being cocky, he asks if anyone else wants to tangle with him and they all, naturally, recoil in fear.
Following the short scene where he drains Dr. Drury of his blood to regain his visibility and burns down the house in the process, the climax begins when, while having lunch with Julie and Mark Foster at the Herrick dining table under the alias of Martin Field, Griffin realizes that he's fading away again and feigns having cut his hand as an excuse to get out of the room. Rushing upstairs, he sees that the maid, Norma, is in his room and quickly improvises by covering his now almost invisible head with his shirt as he rushes into the bathroom in the back (he doesn't close the door, which he should have). He tells Norma to tell Foster to come up to his room when she can talk to him alone. When Foster receives the message and walks up to the room, he finds it empty but sees a note on a lamp table that says that the Invisible Man is in the house and that the clue has led Field down into the wine cellar. Walking down there, Foster turns the light on but sees no sign of Field. When he walks further in, the now completely invisible Griffin locks the door behind him and takes away the key. Foster walks around for a bit, continuing to look for Field, when he finds his clothes on the floor and a small, blood transfusion apparatus on the table. Griffin makes his presence know by taking it out of his hands and says, "I told you you'd find the Invisible Man down here," laughing as Foster attempts to run out the door, only to find it locked. Foster tries to give himself an advantage by turning the lights out but gets shoved to the other side of the room as Griffin turns them back on. He throws a wine bottle at the door but misses Griffin, and misses him again when he tosses a milk creamer, taking out the light. Griffins grabs Foster by the throat and tells him that he needs his blood before shoving him against a wine barrel behind him, knocking him to the floor. As he gets up, he's grabbed by the throat again and punched in the jaw, Griffin telling him his intention to marry Julie, but he manages to gain some leverage and kicks him into the table behind him. Foster grabs a stool and tries to use it to break down the door but Griffin takes it away from him and knocks him over the railing along the steps. Foster throws another wine bottle, missing again, and runs to another spot of the room after grabbing another, all while Griffin laughs at his helplessness. He gets knocked backwards over a wine barrel on the floor and Griffin then takes the bottle away and smashes it over his head, knocking him cold.
Griffin props the table back up and places the unconscious Foster on it, preparing for the blood transfer while putting his clothes back on for modesty (modesty, that is, for the censors). Outside, Higgins is trying to take Drury's vengeful dog, Brutus, somewhere where he can kill him, when chief constable Sir Frederick Travers drives up with a man who claims that he picked up someone near the scene of Drury's murder and dropped him off at the Herrick house. Travers tells Sir Jasper that they'll have to see this "old friend" of his who dropped by but when they go inside to do so, Brutus barges his way in, pulling Higgins behind him. Down in the wine cellar, Griffin is slowly regaining his visibility, while Brutus makes his way down the stairs to the locked door, Higgins unable to stop him. Brutus barks at the door, knowing Griffin is in the room, as he continues to become solid, while Travers questions Higgins as to why he happens to have the murdered man's dog. Higgins blurts out Griffin's real name while trying to explain and when Travers overhears Cleghorn tell Sir Jasper that Field isn't in his room, they all proceed to break the door down with a bench. Griffin sits up, still partially transparent, when Brutus rushes into the room once they've made a big enough hole in the door. Griffins grab a bottle and the two rush at each other, and after a cut that shows the others continuing to break the door down, Griffin is shown being overpowered and forced down to the floor by Brutus. Once they completely break the door down, they see Brutus mauling Griffin and manage to pull the dog away, although Travers sees that it's too late: the Invisible Man is dead.
I can't say much of anything about the movie's score, because I barely remember it. I think it's a completely original score again, although the fact that H.J. Salter is credited when William Lava and Eric Zeisl also had a hand in it makes me wonder if parts of it were taken from other sources that I'm currently unaware of (some parts of it were a tiny bit familiar but I could be wrong, since a lot of the music used in this films sounds very similar). Regardless, aside from silly-sounding music during the scene at the bar, I don't remember the details of any parts of the score, including the opening theme, which I remember thinking sounded pretty good but I'll be damned if I could tell you exactly what it sounded like. Yeah, I've drawn a complete blank here.