At his print shop in New York, Frank Raymond gets an unexpected visit from four men, two of whom reveal themselves to be Conrad Stauffer, a high-ranking Nazi official, and Baron Ikito of Japan. They also tell Raymond that they know his surname is actually Griffin and that he is the grandson of a man who discovered a formula for invisibility. They offer to pay him a great deal of money for the formula and make no secret of their intending to use it to benefit their countries during the war but when he refuses to give it to them, initially feigning ignorance about it, they threaten to slice off his hand. Griffin manages to escape from them but, despite reporting the incident to a government official, he remains reluctant to allow anyone to use the invisibility formula, including the American government. However, following the attack on Pearl Harbor and America's entry into the war, he reconsiders but only on the condition that he himself be the person injected with the serum and sent on an intelligence mission. Washington agrees and Griffin is then tasked with being dropped into Germany and using his invisibility to learn when and how the country plans to launch an attack on the United States. Once there, he meets up with his contact, a German coffin-maker named Arnold Schmidt, who points him in the direction of Maria Sorenson, a young, female agent who knows some of the most high-ranking Nazis, despite being secretly against the regime. After making his way to her house and introducing himself to her, Griffin listens in on a dinner between Maria and Gestapo officer Erik Heiser, as she tries to get the right information out of him, but when he gets a little too tipsy on champagne and also doesn't like how Heiser is moving in on her, he decides to play tricks on him. When the Nazi loses his temper over whatever's happening and places Maria on house arrest before storming out, Griffin realizes he's messed up and decides that she'll have to meet with Heiser again to make up for it. However, things become complicated when Stauffer returns to Germany, learns of Heiser's botched dinner with Maria, and has him arrested for trying to usurp his position and move in on Maria, whom Stauffer himself has an interest in. He attempts to trap Griffin in his office but the invisible agent manages to escape with a list of German and Japanese spies currently in America and, after having Schmidt pass the information on to England, visits Heiser in prison and learns of a planned attack on New York that very night. Griffin must now reach England with the information but, with Stauffer and Ikito each on their own missions to track him down, Heiser proving himself to be very treacherous, and Griffin having his own suspicions about where Maria's loyalties lie, it'll be easier said than done.
Jon Hall is interesting among the actors who appeared in Universal's classic science fiction and horror films in that he's the only actor to play an invisible person in more than one of their movies (in fact, he may be the only person to play an invisible man more than once, period), as he would become invisible again a couple of years later in The Invisible Man's Revenge. Here, he plays Frank Griffin (the same name of the character that John Sutton played in The Invisible Man Returns), the unwitting custodian of the invisibility serum, which he sees as a dangerous burden that must not be used by anybody under any circumstances, least of all the Axis, who target him for the formula. It takes the Japanese attack on Pearl Harbor to make him realize that it could be very useful to help defend his country but even then, he stipulates that he must be the one who's injected with it and use it to carry out the mission, as only he understands how potent it is. After being given the first step of his mission and injecting himself with it before parachuting out of a plane and into Germany, he gets down to business, meeting his contact, Arnold Schmidt, and is pointed in the direction of the lovely spy, Maria Sorenson, whom he hopes will get Nazi second-in-command Karl Heiser to reveal the date and details of a planned attack against the United States. However, this is where Griffin reveals himself not to be the best secret agent, as he gets a little drunk on the champagne they're serving and when he decides that he doesn't care for Heiser's flirting with Maria, he uses his invisibility to pull pranks on him. By the end of it all, Heiser is so flustered and embarrassed by whatever's going on that he puts Maria under house arrest and storms out. Realizing that he messed up, Griffin tries to make up for it, as well as comfort her when she becomes upset over how the Nazis treat women, by making himself partly visible by using a robe, cold cream to make his face and hands visible, dark glasses to cover his eyes, and a towel to cover the top of his head. It's clear that there's an attraction between the two of them, as Maria is intrigued by what little of Griffin she can see, but the invisibility serum's unpredictability comes into play when it fatigues him to the point where he falls asleep in her room. When Heiser returns to the house later, accompanied by Conrad Stauffer, Maria has to quickly remove every part of his getup from him while he's still sleeping; fortunately, he wakes up at some point and manages to escape detection, and although he falls for an obvious trap by Stauffer, he's able to get away with a list of the German and Japanese spies in America. He then visits Heiser after Stauffer puts him in prison and manages to get him to confess when the attack on America by Germany is happening and how they're going about it. He keeps the promise he made to Heiser and helps him to escape, but things become complicated when he's trapped by Baron Ikito and his men. With the help of Maria, he does manage to escape captivity and make it to England, but he doesn't trust at her at this point, as he suspects that she may actually be working with the Nazis and is only convinced of her sincerity once they're in England.
While we're on the subject of Griffin himself, this would be a good time to discuss the film's connection to the original Invisible Man. As he's described as the grandson of the one who discovered the invisibility formula and was eventually shot by the police, it seems that there is a very concrete connection to the original, except when his grandfather is referred to as Frank Griffin Sr. rather than Jack Griffin. This isn't the first time they've gotten the name of the original Invisible Man wrong, as when you see his file in The Invisible Man Returns, his first name is John (they also inexplicably changed the name of the drug in the serum that caused madness), but this makes it seem like the Griffin here is related to Jack's brother in the second film, who was most definitely not shot down by the police. And maybe I'm wrong but how can a grandfather be "senior" and the grandson "junior?" Isn't that strictly a father and son thing? Plus, even though the serum is described as being potentially dangerous, which alludes to the fact that it can cause madness, it seems to cause moments of extreme fatigue more than anything else, as Griffin falls asleep from it a couple of times. When he said that only he should be the one to use it because he's aware of its potency, does that really mean that Griffin has used it before and has become immune to its maddening effects? Who knows? Continuity was never much of a factor during this period, especially since people didn't have the ability to see earlier movies again and again, and it's such a small part of the story, that it's not that important. It's just something that's fun to think about. And while he remains invisible for the majority of the film, Griffin does manage to put together a disguise that's very similar to that of the original Invisible Man's. He uses cold cream to make his face and hands visible rather than bandages and wears a bathrobe and a towel atop his head to make the rest of himself visible. The cold cream may not be as iconic as the bandages, and the towel on his head is pretty silly-looking, but his look is still a very memorable one and is definitely one of the film's best remembered images, as it is when he puts on the uniform of a Nazi guard and pulls his collar up and puts a cap on to hide his invisible head.
Ilona Massey, who I feel was one of the loveliest women to appear in these movies and who would go on to play Baroness Frankenstein in Frankenstein Meets the Wolf Man, plays Maria Sorenson and, while she doesn't get to bring much to the character, she does, however, actually manage to make her a little more than Frank Griffin's love interest. She's been trained as a spy by the Nazis and puts up with the unwanted attention of both Conrad Stauffer and Erik Heiser but, in reality, despises them and the entire regime for their cruelty and how they treat women, be it when Heiser says that a lovely woman like her shouldn't be a spy and when the Nazi guards shove her aside while searching her bedroom, making her more than willing to help Griffin in his mission against them. However, during their first encounter, she has to deal with both Griffin's own clear interest in her and also with how he ruins her plan to get information out of Heiser, getting her put under house arrest in the process. Regardless, it's clear that she's just as infatuated with Griffin as he is with her, doing what she can to keep him hidden from Stauffer and Heiser when they come to her house later that night and continues to aid him however she can, hoping that she can leave Germany with him. Unfortunately, due to circumstance and being in the wrong place at the worst possible time, Maria causes Griffin to distrust her and he continues to do so even when she helps him escape from both Stauffer and Baron Ikito, make it to the nearby airbase, steal a plane to use to fly to England, and drop bombs to delay the Nazis' planned attack on New York. He doesn't allow her to radio England that they're coming in a German bomber because he thinks she'll betray him and contact the Nazis (again, seriously, Griffin?), which causes their plane to get shot down by the British defense force as he falls asleep at the controls before he has a chance to contact them. He's just lucky that Maria was able to parachute them to safety and get Griffin safely to a hospital, where he's informed that she truly is an Allied spy. The movie ends with them officially becoming lovers, with Griffin having regained his visibility and Maria able to really see him for the first time, which is definitely forced and tacked on but it's to be expected from Hollywood movies of this time, so whatever. Okay, so she's not the deepest, most complex character, but at least Maria is memorable and likable enough, and for me, that's often what matters.
The less than amicable relationship between Ikito and Stauffer comes out in the open during the second half of the film, particularly when Griffin manages to escape with the list of spies in the United States. Ikito, who's staying at the Japanese embassy, visits Stauffer in his office after he hears about what happened and when Stauffer comments on how fast his news service is, saying that he could have beaten the fire engines if he'd been a minute sooner, Ikito adds, "And perhaps caught Griffin?", making no secret of how incompetent he thinks the Nazis are. Suspecting that it's been taken, Ikito brings up the list, which he himself gave Stauffer, saying that it'll cost him his life if it falls into the wrong hands, hinting at the tradition of seppuku, and asks him to show it to him to set his mind at ease. Stauffer, however, refuses, stating that they're on German soil and that their code demands that they each do what's best for their own, individual welfare. Though he remains calm and polite, Ikito, now knowing for sure that their partnership is most definitely not one of trust or good will, decides to take matters into his own hands and track Griffin down himself so he can acquire the invisibility formula for Japan. He also tells Stauffer that he's going to tell the Japanese government of what's happened and Stauffer says he can do what he likes but that he must remember that he's still in Germany; Ikito tells him, "I've never been more aware of it." (However, he later admits that their alliance was only for the benefit of Japan, so that feeling was definitely mutual.) Having overheard Stauffer mention the call that was placed to Maria Sorenson's house, Ikito sets a trap for Griffin at Schmidt's carpentry shop after the Nazis take him in for interrogation, using a net with hooks tied on the inside to ensnare him. He and his men take him back to the Japanese embassy, where the hooks are removed and Ikito tries to persuade Griffin to give up the formula in exchange for Maria, who his men took prisoner along with him. However, the two of them manage to escape, and when Stauffer unintentionally aids them in doing so when he and his men storm the embassy, Ikito decides to punish the Nazi official as well as himself for their part in the failure. Telling him, "I'll make an honorable man even of you," Ikito stabs Stauffer to death before turning the knife on himself.
Like The Invisible Woman, Invisible Agent was given a pretty big budget (again in the $300,000 range) for what was essentially a B-picture but, while the money on that film mainly went into the special effects, here the film itself benefits. While some of them are pretty standard, like the carpentry shop and the prison, there are sets in the movie that are fairly lavish, like Maria's nice, fancy house, where white is the predominant color, Stauffer's large office, and good use of the Universal backlot for scenes that take place on the town square, in the surrounding countryside, and the Nazi airfield. Some of the setpieces are pretty elaborate, like when Griffin parachutes from the plane as it's being fired upon and, once he's invisible, escapes from some Nazis waiting for him; when Stauffer traps him in his office and Griffin starts a fire and uses the intervention of the firefighters who arrive along with his invisibility to escape; and the climax, which involves a lot of chaos as Nazis storm the Japanese embassy, Griffin and Maria creating havoc when they arrive at the airfield, using a bomber that they commandeer to destroy a good number of planes to impede the attack on America and create chaos and confusion on the airfield in the process, and their plane being shot down by the RAF, with Maria having to parachute the both of them to safety (there's some pretty noticeable stock footage during these sequences but it was common practice around that time). The film is also well shot by cinematographer Lester White, with instances of deep, noirish blacks and contrasts in scenes such as when Schmidt first meets Griffin and later when he's being interrogated and tortured by Stauffer and his men, Heiser is in prison, Griffin is captured by Ikito in the abandoned carpentry shop, and in the Japanese embassy during the climax. The camerawork is definitely not fancy or arty in any way but there are some nice shots and setups, like how the opening interrogation towards Griffin is often filmed to show nearly all of the characters in one shot, with Stauffer sitting in front of him and two men keeping him in his chair from behind (once again, I feel like this scene had to have inspired Raiders of the Lost Ark, as it's very similar to when Arnold Toht comes in to interrogate Marion, and the action scene that follows where Griffin escapes is similar to when Indiana Jones fights them off and rescues her), and the close-up of Ikito as he murders Stauffer and prepares to kill himself, with the actual suicide photographed at a distance from behind him.
One of the film's strongest elements is the effects work, and I wasn't exaggerating when I said that it was some of the finest John P. Fulton and his crew ever created for one of these "invisible" movies. In fact, the astounding effects aren't limited to Frank Griffin, as you have a nice use of miniatures, matte paintings, and compositing for shots of the planes flying through the sky and when those at the airfield are destroyed by the bomber, which is quite spectacular. Getting to the invisibility, you can tell that Fulton and company were becoming more adventurous with how they pulled the effects off, with Griffin becoming invisible and kicking off his clothes while parachuting down from a plane, combining the matting technique with a process screen of the night sky in the background and it looks quite good. As in the previous films, you can sometimes see John Hall's matted out silhouette, a faded, soft halo around him sometimes, transparency of certain objects and other things that he comes into contact with (in the first scene between him and Arnold Schmidt, if you look closely, you can see Albert Basserman's own hand disappear when he feels around for Griffin), and wires suspending various items in midair to make it seem as if Griffin is carrying them, but it's easy to overlook because of the restrictions of the times and also because the rest of the effects are very impressive. Case in point, the moments where he's washing up in Maria's bathtub and when he puts cold cream on his face and hands to make himself partially visible for her. Those are simply amazing to look at, as you can see the soap suds sitting on an otherwise completely invisible set of arms and legs (there is a silhouette there but you have to strain to see it), and the cold cream slowly creating an impression of his invisible face and hands. In the latter, the silhouette is more obvious but it's still so cool to look at, especially when the face is half-formed, and the same goes for when Maria takes his glasses and head-towel off and wipes away the cold cream to hide him from Stauffer and Heiser. There are some other noteworthy instances of invisibility, like when Griffin is putting on and wearing a guard's uniform and when the net drops on him, but those, along with the non-invisible effects I mentioned earlier, are where Fulton's work really shines and it's small wonder that he once again received an Oscar nomination (he never won for any of these movies but later in his career, when he began working on more prestigious movies like The Ten Commandments, he would eventually rack up three awards).
Given how far our relationships with Germany and Japan have come since World War II, it's always interesting to look back at films, theatrical shorts, and cartoons made around this time as propaganda that completely demonized and mocked them. For starters, you have only fleeting instances of Nazis either speaking German or, at the very least, in German accents, and the two commanding officers of the regime here, Stauffer and Heiser, are played by a British actor and a Romanian-born American actor respectively. That's to say nothing of Peter Lorre, a man of Austrian and Hungarian birth (and who was also Jewish, having fled Germany in the early 30's to escape the Nazi regime), playing a Japanese. That in and of itself is a little easier to swallow, as Lorre was so odd-looking in the face that he could pass for Asian, especially when wearing the glasses he wears here, but at the same time, it fits with the stereotypical image of the Japanese around that time, as weird and menacing killers (at least they didn't give him buckteeth and have him say, "So, so," in an over-the-top accent). Speaking of which, that's another thing about them: the way in which they're portrayed. While Lorre, Sir Cedric Hardwicke, and J. Edward Bromberg all play their roles as the villains well, there's not much complex or multi-faceted about them, as they're just a group of sadistic, menacing, and evil men who are willing to back-stab and betray one another in order to benefit their own personal causes, with the alliance between Germany and Japan being portrayed as distrustful and anything but respectful. Both Stauffer and Heiser make no secret of the fact that they believe the Nazis are the "master race" that's meant to rule the whole world, with Stauffer telling Griffin early on, "German thinking is the clearest in the world," and, when he's bringing out the food he brought for them, Heiser says, "Every country we conquer feeds us... Slaves working for us everywhere, while we sit back with a fork in our hands and a whip on our knees." Speaking of Heiser, he also makes a comment on the tyrannical, controlling nature of the Nazis, telling Maria, "The Fuhrer doesn't like people who think their own thoughts." And let's also not forget how he in particular is shown to be a buffoon that Griffin makes a complete fool of during the dinner and acts like a big baby when Maria laughs at what's happened, storming out and putting her under house arrest. In fact, the Nazis as a whole are portrayed as incompetent, with Griffin easily besting them whenever he comes up against them, such as when he first lands in Germany, escapes the trap Stauffer sets for him in his office, and during the climax. (Supposedly, there was originally a scene where Griffin gives Adolf Hitler himself a kick to the rear that was cut from the final film when images like that were banned altogether.) All of this is indicative not only of the time period but also the sentiments of Curt Siodmak, given his connection to the material. However, the film only demonizes the Nazis rather than the German people as a whole, with Arnold Schmidt (played by an actor who was German) and Maria Sorenson shown to be friendly to the Allies and staunch anti-Nazis, again obviously due to Siodmak, so it's a little more fair than other such films of the time.
While not a big spectacle movie by any means, there are some nicely done, fairly exciting and entertaining sequences to be found here. At the beginning, when Stauffer, Ikito, and their men interrogate Griffin about his grandfather's formula and he initially refuses to talk, he seems to relent when they threaten to slice his fingers off with one of the cutting devices in his print shop (there's a nice bit of suspense there as Ikito inches the blade down towards his hand, as he's held there by the other men). But, when he takes out a hidden drawer that he seemingly uses to hide the formula, Griffin uses it to knock away one of the guards holding him, smash the overhead light, use the darkness to punch away the other attackers and smash the big window out in front, managing to avoid the gunfire in order to run for safety. Later, when he's dropped into Germany, the plane carrying him is fired upon by Nazi troops on the ground and he quickly injects himself with the serum before jumping, disappearing and removing his clothes as he floats down to the ground, much to the surprise and confusion of the troops who watch him. He lands atop a nearby barn and the Nazis attempt to trap him there but he smashes his way into the barn, uses the hay inside to distract the soldiers who walk in, and manages to get by the others who surround it, commandeering a vehicle and getting rid of its drive in order to make it to Berlin. We get a bit of comedy during the scene where Griffin eavesdrops on Maria's dinner with Heiser and decides to pull a number of pranks on the second-in-command, like making it seem as if Maria's cigarette lighter is automatic but only for her (he continues trying to make it work for him through this section of the movie), popping the champagne before Heiser can do so himself, helping himself to some champagne and food behind Heiser's back, pushing an ice bucket onto him, shoving a fork with mashed potatoes on in into his face, turning the entire table onto Heiser and getting food all over his uniform, and putting a fork on his chair when he sits down. And when Stauffer traps Griffin in his office, Griffin initially tries to escape but finds the door locked and the only other way out a window four stories up with no fire escape. Stauffer forces him to sit in his chair and rock back and forth so he knows where he is, again trying to get him to give up the formula in exchange for his life but when Griffin still refuses, he uses Stauffer's attempt to bring his men in to create a distraction by starting a fire in the room using a floor heater, a waste basket full of papers, and documents in his desk. Griffin then calls for the fire department using the radio on the desk and uses his fists and other objects on the desk to fend the Nazis off until the firefighters arrive, using the ladder they put up to the window to escape with the list of spies in the United States.
The third act begins when Griffin helps Heiser escape from prison in exchange for telling him when and how they plan to attack America, knocking out the guards who come to execute him and using their uniforms so the two of them can slip out undetected, with Heiser adding a touch of firing several shots so the guard at the front desk will think he's been executed (whether or not he actually killed the guards with those shots off-camera is never revealed). But things get complicated when, at Arnold Schmidt's carpentry shop, Griffin and Maria are captured by Ikito and his men and taken to the Japanese embassy, prompting Heiser to attempt to save himself by telling Stauffer what's happened in exchange for being reinstated in his position. But, just as the Nazis arrive outside the embassy, Griffin manages to knock out Ikito's men who try to remove him and Maria from the scene, and when Stauffer and his men storm into the embassy and battle the Japanese, the two of them use the chaos and confusion that breaks out to escape, commandeering a truck outside to drive to the airfield. Heiser takes command after Ikito murders Stauffer and tries to chase them down, unaware that two of Stauffer's men are after him, but is unable to stop them from reaching the airfield. There's a lot going on here, as Griffin barrels past motorcycles, guards, and other obstacles in his way to reach the field, turns over a gas tank there, creating a fire that engulfs much of the field and distracts the Nazis while he carries Maria over to a nearby bomber. Heiser arrives just in time to see the bomber take off and orders them to man the other planes and shoot it down, but Griffin destroys the remaining planes with the bombs, turning the airfield into a full on warzone. He and Maria fly away, avoiding the big turret guns that shoot at them, and Heiser is gunned down by Stauffer's men. They run into some more trouble when they enter English airspace, as Griffin refuses to let Maria notify the British that they're in a German plane because he doesn't trust her and as a result, they're fired upon. To compound things, Griffin falls asleep from the serum again and Maria has to parachute them both to safety, as the plane is soon shot down. They have a rough landing and English troops arrive to take them in but the next scene shows that they're now in safe hands, with Griffin recuperating and Maria's sincerity proven to him, before they officially become lovers.
This was during the period where Universal, in order to cut costs, reused music from their past films to score new films and Invisible Agent, as I don't think there's a single bit of original music to be found here. It's all taken from other movies, notably horror films like The Wolf Man, and is re-orchestrated and re-arranged to sound somewhat different but it's instantly recognizable if you've watched a number of these movies like I have. As a result, there's not much I can say about this. What they used fits the movie okay but it's just a shame that a number of flicks made during this period, like Frankenstein Meets the Wolf Man, House of Frankenstein, the latter Mummy movies, and so on weren't afforded their own musical identities, as it really affected the memorability of some of them.