Enterprise hosts an Medusan ambassador and a telepathic doctor.
This is an enjoyable episode with some good themes and strong performances.
The plot has a lot of emphasis on dialogue as it focuses heavily on guest characters and their interaction with the Enterprise crew. I would not describe it as a compelling screen story, but it is very interesting.
It contains a number of literary connections with its characterisations and quotations, and it philosophises on the nature of truth, beauty, physical form, and connections between individuals.
It is quite distinct from most other episodes in its complex portrayal of characters. Dr Miranda Jones is one of the great guest characters of the original series, who is written as strong, intelligent, quick-witted, having the power of telepathy, but she also suffers very human failings such as jealousy. Diana Muldaur gives a typically powerful and charismatic performance in this role.
Dr Jones' interaction with male characters like Marvick, Kirk, and McCoy involves them pitching lots of objectification and patronisation her way. Refreshingly, for a female character written in the 60s, she smashes each bit of dated sexism out of the ground for a home run. She is not interested in being idolised for her physical beauty or attain the love and admiration of men. She has an ambition so big it actually transcends humanity.
Kirk and Bones are rather unusually and intentionally portrayed as lecherous, and this works well for the episode themes and Dr Jones' arc.
Spock has an important role, with his Vulcan physiology and mental abilities being crucial to a key point in the story. Leonard Nimoy has one of those rare opportunities when he can be emotional and it is enjoyable to watch.
Visually I think it is excellent. There are a number of unique camera angles rarely used on Star Trek that are effective. I also liked the trippy, flashy green light sequences. Non-humanoid creations are always a plus for me in the franchise. As stated in multiple other reviews, the issue with Kirk at the transporter near the very end is poor continuity, but it doesn't spoil the episode for me.