(With apologies to Hrtsonslv - the style of my single summary line above is shamelessly redolent of his own)
Three hours before a sun blows the Enterprise decides to pay a visit to its orbiting planet - that's cutting it kind of close, don't ya think? Despite the consistency questions in this episode, it still ranks as one of my all-time favorites. The whole notion of Zarabeth's isolated loneliness, mirroring Spock's own brand of desperate solitude, forever strikes a chord.
"Do you know what it's like to be alone....really alone?" Zarabeth asks Spock. "Yes," he replies simply. Had McCoy not been along, we most likely would have seen the last of Spock, and who could blame either him or Zarabeth?
As an adult, the questions raised about this episode were never there when I was a kid, though - maturity robs one of so much! For example, where exactly does the lighting in Zarabeth's cave come from? We see three or four candles throughout the area, but that's hardly enough to give it the stunning ambiance which eventually aids in her and Spock's mutual seduction. Another thing: if Zarabeth existed 5,000 years ago, and Spock consoles himself with the knowledge that she is now dead and buried (who would have undertaken her funeral arrangements, by the way?) how was it possible that she heard the voice of Kirk along with Spock and McCoy through the other side of the portal?
Of course, the cynic in me shouts the following kinds of things at the television: "Nice outfit, Zarabeth - whatever did you skin to get those skimpy little threads? A rabbit?"
Then there's the woman who Kirk gallantly tries to rescue from her taunters. She's not unattractive, but the Captain's only would-be female target in this episode has a few too many lines around her eyes to be compelling for Jim. Therefore, Kirk does not try to enlist her help, and it is Spock who gets lucky in this episode.
If anyone is a great fan of this episode, I would highly recommend its sequels, which I read as a young adolescent: Yesterday's Son in which Spock meets the product of his union with Zarabeth for the first time, and Time for Yesterday is even better.