Truth be told, I'm far more familiar with the 1995 remake that I didn't actually know was a remake until stumbling upon this title for my Classic Horror Review list. I saw the '95 version quite a while ago, and pretty much thought it to be stupid, but not without a creepy moment or two. In looking back to the original, it actually turns out that much like 'Psycho', the remake is just about shot-for-shot, with any differences being incredibly subtle. That said, there's a touch more of something I got out of this, but more on that later.
The film opens in the small British town of Midwich, where everyone suddenly seems to drop dead from some invisible force. As the military blocks roads into town, they send in one of their own with a gas mask, and he too falls victim to whatever this mystery is. However, when thy pull him back, they discover that he, and seemingly everyone else in town is merely unconscious. A little while later, everyone who survived the ordeal comes to (some people have crashed cars and even planes during this "blackout"), and life carries on, but with one bizarre exception - every woman in town able to bear children is now pregnant.
These fetuses grow at an alarming rate, getting into the 7-month phase of development at about 5 months. All of these women give birth on the same day, and all of the children have the same specific physical features that include hair and eye color, along with oddly narrow fingernails. As the children grow up, they get more in more in tune with their telepathic abilities, and it's further discovered that they work on a sort of hive mentality. The same thing evidently happens in other parts of the world as well, but not much goes back to that idea.
When these kids get into their puberty days, these children become downright creepy, and many of the villagers end up living in fear of them. They speak like distinguished adults, dress every day like it's a fancy event, show no signs of real conscience or love, and are generally cold and zombie-like. For an easy go-to reference, check out the 'Simpsons' episode 'Wild Barts Can't be Broken' from Season 10 (definitely one of the better episodes of the series downward turn). They also learn that they can take control of opposing adults by making them do what they want, providing the audience with that eerie eye-glow you see in the accompanying picture.
I think this is a fine example of one of those horror themes I just don't quite understand completely. The idea here is to make children the thing to fear, and children can definitely be downright creepy on their own (just check out this link). It's likely effective for its time and for parents with overbearing children. But I'm a bachelor who tends to get along with my friends' kids pretty well, so the idea of a straight up evil kid doesn't fully compute with me (although there are exceptions, like that time Hitler was a child), and this is nothing but over-the-top supernatural. It's eerie to me, but not exactly scary, and I just don't have a whole lot more to say about it. It's.... average.