How do you follow The City on the Edge of Forever? Not easily, but Operation – Annihilate! does have a nicely grim tone (especially from Kirk) which given the events of the previous episode fits nicely.

Kirk is very snappy throughout. The reason is obvious (Jim’s brother, sister in law and nephew live on a colony planet called Deneva, currently in the grip of an outbreak of mass insanity) although it’s still jarring to see him snap at Uhura for no good reason.

This downbeat mood also infects McCoy, who later has a short argument with Nurse Chapel about the best way to treat Spock. All of these moments help to disguise the fact that there’s a rather pulpy science fiction idea at the heart of this episode.

Whilst they may look less than impressive today (flying pancake-like objects moved around with fishing wire) back in the 1970’s the parasitic organisms who are driving planet after planet mad were the very stuff of nightmares.

We never learn a great deal about them. They just seem content to move across the galaxy in a straight line (why?) infecting each new planet they arrive on. Given that their rate of progress is quite slow (measured in years)  I’m not sure why it wasn’t decided to evacuate Deneva before they arrived.

I do like the way that today’s eye-candy Yeoman (played by Maurishka Taliaferro) ventures the opinion that the parasites don’t look real. It’s a dangerous game to play though – once you start pointing out how absurd or artificial things are, you’re on a slippery slope ….

As often with Star Trek, guest roles are few and far between. There may be a million colonists on Deneva, but they’re represented by several pipe-wielding types and Jim’s family. Kirk’s brother, Sam, is dead when he arrives and Sam’s wife, Aurelan, follows shortly afterwards. Although not before she’s done a great deal of screaming and wailing.

This leaves Jim’s nephew, Peter, and it’s maybe not surprising that Kirk’s focus is on him (and also Spock, after he gets infected). McCoy angrily (as already touched upon, there’s a fair few raised voices in this one) reminds him that all the colonists are his responsibility, not just these two, but it’s a plot point that doesn’t really go anywhere. A pity, as there might have been some dramatic capital to be mined our of Kirk’s personal/professional conflict.

Spock’s internal battle with the parasite is a highlight of the second half of the episode. As is Scotty preventing a rogue Spock from beaming back down to the planet. James Doohan, like all the second string regulars, often had very little to do – but he was always well worth watching anyway.

Operation – Annihilate! is a strange mixture of downbeat storytelling and pulpy SF (the fact that the episode title has an exclamation mark in it suggests that we shouldn’t take this one too seriously). It’s one of those episodes that tends to get overlooked (despite being the series one closer) but I’ve always enjoyed it.