Following The Invisible Woman, The Invisible Agent would take some bits from each of the films that preceded it except for one notable exception and that would be the horror element that pervaded the first two.  So while it would retain some comedy, it would then introduce a little espionage into the mix and create a war film that is a little formulaic, but also fairly original as well.  It would star Jon Hall in the lead role as the grandson of Jack Griffin, the creator of the invisibility formula.  It was good to see Curtis Siodmak tie the film back to the beginning, once more creating a continuity throughout the franchise and ignoring the previous film in the process.  While the last film was good, it worked better as a standalone than anything else.

Here we find our hero living the quiet life until some Nazis uncover his secret and try to claim the invisibility formula for themselves.  Luckily, Frank is able to fend them off and get away.  After Pearl Harbor gets bombed, Frank decides that he will use his formula to go undercover and spy for the U.S. and it is then that he discovers that the Germans have a plan to bomb New York City.  Now all he has to do is evade them all and get back to where he can make his report from safety and hopefully avoid a catastrophe.

As far as the plot goes, it was all right if fairly standard as far as war films go, but factoring in an invisible man gave it a little extra kick in the pants and made it a bit more exciting.  Jon Hall did a good job in the lead and would prove to be both charismatic and effective as the rookie spy out to save the world.  The film also boasted a top-notch supporting cast with Sir Cedric Hardwicke once again playing the villain of the picture and the aforementioned evil Nazi who tried to get the formula at the beginning of the picture.  In league with Hardwicke’s character is the great Peter Lorre playing a Japanese spy of all things.  If there is one thing you can say about Lorre, it is that the man has played all sorts of roles over the years and he has never been boring.  Rounding it out is the beautiful Ilona Massey who would star in this before going on to another Universal property called Frankenstein Meets the Wolf Man.  Massey and Hall would have good chemistry in the film and seeing them banter about being invisible or whether or not she was a double agent was a lot of fun.

By this point in the series, the Invisible Man movies no longer resembled the original work done by H.G. Wells and by straying so far from the source material, they kind of lost the magic that was present in that very first film.  There is still that twinge of science-fiction but everything else has been purged in favour of trying new things.  That is not to say that testing the waters to see what floats is bad, but when you have a formula that works, why not improve upon it instead of diluting it?  A little horror would have been nice and you have to wonder why Frank did not go mad like his predecessors did when they used the formula?  Overall, The Invisible Agent was an enjoyable spy thriller despite not being a true Universal horror.  Again, like the previous film, it almost works better as a picture standing by itself than anything else, but at least they tried to bring it back to its roots.

3.5 out of 5