[[caption-width-right:320:Kirk and Nona.]]

Kirk, Bones and Spock beam down to a peaceful, idyllic planet where some years previous Kirk had befriended a native called Tyree (Michael Witney). It looks like the friends may get a chance reunite, but it looks like they're going to be ambushed by another group of tribesmen armed with flintlocks. Which is odd, because this society is supposed to still be in the Bronze Age. In the ensuing melee, Spock gets shot and has to be taken back aboard the ''Enterprise''.

While Spock convalesces, Kirk and Bones beam back down to investigate this on going war. It seems those darn Klingons are at it again! They convinced one faction of natives that they could be more powerful than the others. All they needed was better weapons. As if dealing with them wasn't bad enough, there are these critters called the mugatu to contend with. Kirk gets poisoned by one. Fortunately, Bones is able to get him to Tyree's tribe, where his wife Nona (Nancy Kovack) is able to heal Kirk.

But Nona's services are not free. She insists that Kirk give her a weapon more powerful than what the Hill People have. And what Nona wants, Nona gets.

* ActualPacifist: Tyree. Until the end.
* TheBroCode: Even Kirk must live by it! At least, he tries to.
* CaptainsLog: Used in every episode, but at one point, the narration switches to the medical log with Bones narrating since Kirk is indisposed.
* CensorDecoy: There was a scene where Nona showed some skin getting out of the water. A flash of bare breast was there to distract the censors. Sorry boys! It didn't distract the editors for the remastered editions! Another possible example is Spock's gunshot wound. A wound that gory usually wouldn't get past the censors of the time. But, as Spock was given [[BizarreAlienBiology green blood]], the censors overlooked it.
* ChekhovsGun: Early in the episode, Kirk identifies Mugatu tracks. Not long after, he gets attacked by a Mugatu.
** This leads to another one--after [=McCoy=] kills the mugatu, Tyree tells him its mate will be nearby. Guess what shows up near the end.
* CruelToBeKind: Spock needs to be put in pain to be brought out of his trance. Scotty pulls Chapel away from Spock, thinking she's gone mad, slapping her patient around. Then M'Benga steps in and gives Spock the back of his pimpin' hand.
* CrusadingWidower: Tyree becomes one.
* DoesThisRemindYouOfAnything: The episode is an allegory of the then ongoing [[UsefulNotes/TheVietnamWar Vietnam War]].
* DownerEnding: The episode ends with the two factions going into all out war and arms race with Kirk ordering up several hundred "serpents for the Garden of Eden", as Kirk poetically refers to the flintlock rifles.
* FemmeFatale: Nona will do anything and anyone to get what she wants.
* FlorenceNightingaleEffect: Nurse Chapel falls hard for Spock.
* FriendshipMoment: Bones shows a lot of concern and care for the ailing Spock and only agrees to leave him with a doctor who has worked extensively with Vulcans. At the end of the episode, they're back to snarking each other.
** Also, when Kirk tells Scotty to take the conn so that he can go to Sickbay and check on Spock.
* GenocideBackfire: We see how this gets started.
* GettingCrapPastTheRadar: The [[DoesThisRemindYouOfAnything orgasmic thrashing and sudden climatic end]] when Nona casts a spell over Kirk's body. Also the scene where Kirk catches Nona bathing naked; the producers left in a breast shot knowing the censor would 'force' them to cut back to the titillating glance the audience got instead.
* GivingRadioToTheRomans: Giving guns to the cavemen.
* HarsherInHindsight: Kirk says that the conflict in Vietnam was resolved by making sure both factions were equally armed with neither becoming stronger than the other. Real life solution? Run like hell!
* HealingFactor: Nona cuts her hand to heal Kirk. Once she's done, the cut heals itself instantly.
* HitMeDammit: Spock tells Chapel to hit him to bring him out of his trance. She gives him a tap that wouldn't hurt a baby. He demands that she hit him harder.
* KissingUnderTheInfluence: Nona uses a certain plant as an aphrodisiac to make men fall in love with her and do what she wants. Tyree is a sucker for it. Kirk finds it rather difficult to resist.
* KlingonScientistsGetNoRespect: "Research is not the Klingon way."
* LaymansTerms: A Klingon explains that "rifled barrel" means the weapon will shoot further and more accurately.
* LowCultureHighTech: The people of this planet are cave dwellers now armed with flintlock guns.
* LoveMakesYouStupid: Tyree doesn't even try to resist Nona's charms. Not even when he sees her using them on Kirk behind his back.
** Not to mention seeing Nona seducing Kirk using the same aphrodisiac that she actually told him about before, and getting jealous of his drugged friend.
* NubileSavage: Nona, of the furry bra and denim skirt variety. Her clothes look suspiciously new and clean, and she has makeup as well.
* OrganDodge: It's a good thing Vulcans have their liver where a heart would be expected.
* OurMonstersAreWeird: The mugatu looks like a cross between Franchise/{{Godzilla}} and Snowflake the Albino Gorilla. Oh, and it has a poisonous bite.
* PatrickStewartSpeech: Eat yer heart out Picard! Kirk beat you to it, pointing out how humanity was once like Tyree's people and in time they too could emerge as a peace loving, intelligent society.
* ScrewTheRulesImDoingWhatsRight: Kirk was advised to stay out of this private little war, but he didn't like the idea of Klingons instigating a war and making things uneven.
* ThouShaltNotKill: Tyree's moral code. Until his wife is killed.
* TooCleverByHalf: Nona uses all her guile to get her hot little hands on a phaser. However, she doesn't know how to use it and is killed by a stab from a simple knife.
* WhatTheHellHero: Bones gives this speech to Kirk when Kirk tells Tyree he will give him weapons to defend himself against his enemies. However, Bones doesn't have any better ideas.
* WitchDoctor: Nona uses herb lore and a bit of mysticism to heal Kirk.