Our hero is Frank Griffin, grandson of the original invisible man. He rejects requests for the formula from both the Axis and the Allies, until Pearl Harbor is bombed and he decides to give it to the US military and become a spy himself.
Peter Lorre! Yay! Playing a Japanese man. What?
I’m not sure how the invisibility effect was done in this one, but you can often see the actor faintly superimposed against the background.
Anyway, the plot is pretty simple: invisible man spies on Germans, learns of a plot to attack America, thwarts the plot, saves the day, gets the girl, etc. There’s no mention of things like invisible eyelids, but the invisibility drug does cause narcolepsy for some reason. It also wears off after a certain period of time, which is convenient since it’s exactly the amount of time required to complete the mission and wake up in the hospital with the Love Interest at your side.
All in all, it’s a pretty meh movie, but it’s nice to see the invisible man as a hero for a change.