This has always been a favorite of mine. I think its because the arrogant get their comeuppance. It involves a diplomatic mission to quite an advanced planet, Eminiar, rich in technology. The Enterprise has been warned away, but Kirk feels he needs to check things out. What he finds is civilization that has been at war with another planet for centuries. However, they fight their war with computers. Buildings and material objects are spared, but the people voluntarily allow themselves to be disintegrated in death chambers. Enter Fox, an insufferable negotiator who thinks that he can talk his way through the barriers put up by Anan 7, the leader of the planet. Because Kirk and Spock are stuck on the planet, Scotty takes the helm. The problem is that the computer has informed Anan 7 that the entire crew of the Enterprise has been designated as war casualties, and he has told Kirk to get his crew to the surface and have them report to the death chambers. Despite the Prime Directive, Kirk isn't going to have any of this. He finds Anan 7's reasoning disgusting. War is supposed to be a dirty thing, meant to be avoided, not some sterile thing. Of course, Kirk also hooks up with Anan's daughter who is beautiful and also listed as a casualty. The sparks fly for a while and I find the conclusion really quite satisfying.