Bem
An alien observer allows himself to be captured by aborigines to test Kirk and Spock's rescue abilities. But Bem finds the planet protected, and his Enterprise "friends" none to happy with proceedings.
Bem is an intriguing character, particularly in being a colony creature (an idea also presented in More Tribbles, More Troubles but better used here) and quite arrogant. The planet is quite commonplace: aborigines (not a proper term) under the protection of a super being. The superbeing sounds suspiciously like Uhura: apparently they couldn't hire more than one female voice that week. There is one golden scene, when Kirk and Spock sit in wooden cages and observe how often they find themselves locked up and tied down. Quoth Kirk: " How come we always end up like this?" Hee hee. Motives are pretty muddled, particularly the super being, who seems to buy whatever Kirk says. Bem is also humbled a little too easily. This was adapted from a live-action script, and would have been better if spread to TOS's 45 minutes. A good actor could also have made all the difference, rather than Jimmy Doohan, again.
Spock Saves the Day: Spock links the communicators to extend their range.
Oops: ...but otherwise fails to help out with his Vulcan abilities.
Developments: A particularly good bit of dialogue as Kirk asks: " Can't you do a... Vulcan nerve pinch?" and Spock replies " I am only a Vulcan. There are limits." This is both a nod to all the times Spock helps them out of confinement with his unique abilities, and an acknowledgement that he's not actually all-powerful. Kirk needs reminding, sometimes.