Only because I am an enlightened man of the 21st century can I see that the Devil Girl From Mars — providentially named "Nyah" — is simply a prototype for the kind of post-modern woman we see all around us, usually in hordes, and only rarely in spaceships.
In the 1954 film, Nyah comes to Earth for a bit of recon and resupply. Seems the sexes fought a hellacious war back home and while the women won, as is only right and proper, they are about out of men for breeding purposes.
So naturally she heads for England, but gets lost. (She apparently does not realize that not reading the map and getting lost is a man's job, and nor should she care. We must smash these conventions and be post-modern.)
So up in Scotland, there's a professor and a reporter looking for the flying saucer; a murderer who has escaped from prison and hoofed it over the moors to come to this little hotel because the serving girl is cute; a beautiful girl from London who is getting over some sort of romantic snarl; a little boy, and the elderly Jamiesons, who run the joint.
And it is here that Nyah decides to make her stand.
In keeping with the latest post-modern ideas about femininity, wears a cap that might double as a bondage mask, ice-skating dresses and death rays. She also has the controls for the Robot, which looks like what happens when flower pots and Kleenex boxes mate.
The brave men in the party try a bunch of lame tricks on Nyah, and it is to her great credit that she doesn't stick her tongue out and say "Nyah, nyah, nyah" which in addition to being her name is a classic playground taunt and as such would have made for some great post-modern irony.
I won't spoil the ending for you because it's so short. Excellent post-modernism. Tremendously ironic robot. Incredibly hip leather skirt. Murderer with heart of gold. Stupid professor. Coy references to sex and alcohol, which in post-modern context are very ironic and fulfilling to women. By all means see this as soon as possible.
(Although experience tells me I don't have to look to Mars for a Devil Girl. There are plenty here already. Nyah nyah nyah.)