This has an interesting message. The people living in the clouds literally cannot connect a bit to the troglodytes who labor below. It is a typical example of the haves and the have- nots. The cloud people luxuriate and pontificate with no regard for those that butter their bread. Of course, a revolution is going to happen and those trogs are going to infiltrate the cloud kingdom. Those buggers in the sky talk with incredible disdain. What they don't realize is that the two peoples came from the same DNA. The poor miners have been unable to evolve because the substance they mine has a detrimental effect on their brains. Kirk, who of course is drawn to the female of the bare shoulders again, decides that something is wrong and tries to bring the two sides together. What happens when this takes place, much to the disdain of the cloud minders, is the point of all this. It's an above average episode with an interesting view of the world.