One drawback to this episode is the startling revelation about one of the main crew members in the pre-credits sequence: there's a scene in this early section which has so much dramatic impact that the rest of the episode cannot help but be somewhat anti-climactic in comparison. The plot has to do with one of those enclosed worlds concepts well known in science fiction: the inhabitants of a huge ship built inside an asteroid believe themselves to be on a typical planet - their 'sky' is actually the inner shell of the asteroid - similar to the hollow Earth concept developed by Edgar Rice Burroughs for his Pellucidar sci-fi/fantasy stories. It's intriguing and fanciful; the people of this Yonada have a different (and erroneous) view of the universe. They're not stupid, simply misinformed, and need someone like Kirk and his crew to explain the reality of things, kind of like getting away from the whole 'the Earth is flat' view. The hook to the episode is that things need to be righted pretty fast - Yonada is on a collision course with a planet, set to strike in a little over a year.
This isn't that bad of a 3rd season episode, but it doesn't really go anywhere with the intriguing concepts. The story falls back on the now-tiresome 'ruling machine gone wrong' plot, with any of the lackluster tension stemming from the main Enterprise trio getting zapped by this Oracle-instrument as punishment (I also wondered why this machine resorted to heating a room at the end instead of the tried-and-tested zapping attack). The one deviation of the usual scripting is that the high priestess of these people falls for McCoy instead of Kirk (or even Spock or Scotty). This episode is McCoy's story all the way and actor Kelley gets the opportunity to show some range here, further developing the sober dramatic aspects of his character. However, as with the rest of the story, the good set-up is abandoned towards the end: out of necessity, McCoy essentially abandons (not divorces) his new wife and life to continue his adventures on the Enterprise, so that we can see him in a few more episodes for the rest of the 3rd season. If there had been a 4th season, we may have seen a sequel to this episode then. As it is, we never find out what happens regarding the McCoy-Natira relationship, and that's a shame. Or a cheat, if you will.
This isn't that bad of a 3rd season episode, but it doesn't really go anywhere with the intriguing concepts. The story falls back on the now-tiresome 'ruling machine gone wrong' plot, with any of the lackluster tension stemming from the main Enterprise trio getting zapped by this Oracle-instrument as punishment (I also wondered why this machine resorted to heating a room at the end instead of the tried-and-tested zapping attack). The one deviation of the usual scripting is that the high priestess of these people falls for McCoy instead of Kirk (or even Spock or Scotty). This episode is McCoy's story all the way and actor Kelley gets the opportunity to show some range here, further developing the sober dramatic aspects of his character. However, as with the rest of the story, the good set-up is abandoned towards the end: out of necessity, McCoy essentially abandons (not divorces) his new wife and life to continue his adventures on the Enterprise, so that we can see him in a few more episodes for the rest of the 3rd season. If there had been a 4th season, we may have seen a sequel to this episode then. As it is, we never find out what happens regarding the McCoy-Natira relationship, and that's a shame. Or a cheat, if you will.