I'm slightly disappointed this isn't called "The Squire of Qo'nos"... you may or may not get that.
As our favourite starship is about to cross a void in space that supposedly contains no planets, one turns up on the scope. Then Kirk and Sulu disappear off the bridge, taken off the ship by Trelane, a superbeing who has a considerable amount of flamboyance but not a lot of maturity.
I'm going to start this episode by discussing the 'guest' of this episode, Trelane, a world-creating super-being who has developed his ideas from Earth through long-distance observation, but his history is a bit inaccurate; apparently he's looking at Earth 900 years in the past because of the whole speed of light thing... which considering that the stuff in his house is of Napoleonic vintage, rather flies in the face of the later established Trek timeline placing this series in 2264 - this had not yet been determined by the writers.
Trelane, played by the late William Campbell, who was very active in the convention circuit for much of his later life, manages to be one of the most watchable and simultaneously most irritating people you will ever see; a strong performance by Campbell. The 'retired General' Trelane is an immature brat with a powerful machine, managing to 'mention the war' as soon as he discovers a crewmember is of German descent, mistake Uhura for a captured slave. It makes you want to slap him, but at the end of the episode, you end up changing your mind; for there is a very good reason why he is like that.
At one point, Trelane dressed as an English judge (apparently there was some difficulty in finding a wig... or more specifically Shatner agreeing to allow time to find said wig), plans to hang Kirk; this is of note for me as a British opponent of capital punishment myself; it had only been two years since the final British executions were carried.
One big drawback, however, some very obvious green backgrounds in sight in the 'outdoors scenes' and a dodgy split-screen effect at the end; even Doctor Who in this period generally made more of an effort than this.
A well written episode with a great twist at the end; the relatively small number of guest cast allows for a tighter episode that keeps you engaged through its whole running time.
However, some obvious effects issues mean I can only give this 8/10.
The next episode is "Arena"; another one I've seen before and also one featured in Mythbusters... more to be explained next time.