Is There in Truth No Beauty?
The Enterprise transports a Medusian, a race so "ugly" no human can look on them without going mad. The telepathic Miranda Jones accompanies him, a delicate beauty with secrets.
The crux here seems to be Miranda's overcoming of her jealousy for those with superior abilities (like Vulcans) and accepting her limitations. However, it's still a pretty sexist conceit, and Dr. Jones is right to feel frustrated and unable to trust the officers treating her so poorly. The most telling example is Kirk's attempt to distract her in the flower garden, assuming she'll be unable to accept a harsh truth. Marvick is almost as bad, unable to accept that she can't love him. His "madness" gives the episode its plot - a weak one. There are too many things left unclear: what is it about the Medusians that causes madness? How is an ordinary human, Miranda, able to attain Vulcan-like mental abilities? How does she save Spock? Why does he forget his glasses? Only the IDIC pin is really memorable, and even that was a tie-in to some mail-order jewelry scheme Roddenberry had going. No truths are revealed here.
Spock Saves the Day: Spock mind-melds with Kollos and navigates his way back into the galaxy from which the ship was flung.
Oops: Big oops with the goggles. Our theory is that Kollos made him forget, since the being's ethics are never explored.
Developments: As mentioned, the idea of Infinite Diversity in Infinite Combinations is most memorable. Many fans have personally adopted the ideology. Considering Spock is Miranda's "rival," he actually treats her best, only going behind her back on Kirk's orders. The mind meld is not new, and Kollos simply makes the Vulcan more smiley, like Hennock in Return to Tomorrow but not evil. (Or is he? Who knows.)