Pros: First Appearance of the Klingons. Great Anti-Colonialism Allegory.
Cons: The Organians are annoying, not only to the Captain and Klingons, but to the Audience.
Star Trek: Season I, Episode XXVI: An Errand of Mercy (1967) Directed by John Newland, Written by Gene L. Coon, Created by Gene Roddenberry
[After being shoved by an arrogant Klingon soldier, and stopped from retaliation by Spock]
Captain James T. Kirk: You didn't really think I was going to beat his head in, did you?
Mr. Spock: I thought you might.
Captain James T. Kirk: You're right.
War is brewing between the Federation and the Klingon Empire. The Enterprise’s mission is to go to Organia and secure the rights to use the planet as a base in the upcoming conflict. More to the point, it must be denied to the Klingons. But Organia, for such a backwards agrarian planet seems curiously unconcerned with the coming invasion.
Kirk and Spock (William Shatner and Leonard Nimoy) are speaking to the council of Elders when an invasion fleet arrives. Lt. Sulu (George Takei) flees before superior forces, leaving the Captain and First Officer trapped on the planet below. Now, the Organians are concerned, not about the Klingons, but about their guests safety, and Kirk is disguised as a local, Barona, while Spock is dressed as a Vulcan Merchant dealing in Kevas and Trillium.
Kor (John Colicos) is a military man. He doesn’t like being given a civilian population to control. Worse, he dislikes one that is so easy to control. The Organians smile and do what they are told. That is why Kor makes Barona his liaison; Barona (Kirk) displays honest hatred. Ayelborne (John Abbot) and his fellow Organians just smile and agree. Can Kirk and Spock take on an entire Klingon regiment and lead the Organians to fight for their freedom? According to Spock, the odds are 7543.7 to one.
This is the first appearance of the Klingons. Yes, I know; the twenty-sixth episode. But really, here they are for the first time. Nor do they reappear until Season II. Kor describes his people as militaristic, expansionist, and ruthless. He is, in point of fact, the American Industrial War Machine personified; a killer, intelligent, ruthless, but not unaware of his own role in things, just not willing to try to change anything. What is funny is the ‘enlightened’ is every bit as military minded, and just as cunning, with quite a broad streak of ruthlessness himself. The entire episode is a blatant critique of the Vietnam War, so much so that it is sometimes called the Vietnam episode. It’s anti-Colonialism sentiments are obvious.
It also is the second appearance of beings of pure intellect, the first, of course being that very naughty boy, Squire Trelane. While Trelane has been identified after the fact as an infantile Q, the Organians are not Q, as will be proven many years later in the Enterprise episode: Observer Effect. I think the solution to this errand was actually a wish by writer Gene L. Coon that the war in Vietnam could be stopped as simply, and as completely as the Organians managed.
To Boldly Go Where No Man Has Gone Before! Star Trek Season I
The Cage (episode 0, unaired pilot)
The Man Trap
Where No Man Has Gone Before (pilot 2)
The Naked Time
The Enemy Within
What Are Little Girls Made Of?
Dagger of the Mind
The Corbomite Manuever
The Menagerie Part I
The Menagerie Part II
The Conscience of the King
Balance of Terror
The Galileo Seven
The Squire of Gothos
Tomorrow is Yesterday
The Return of the Archons
A Taste of Armageddon
This Side of Paradise
The Devil in the Dark
Errand of Mercy
The Alternative Factor
The City on the Edge of Forever