Written by Gene L. Coon and Gene Roddenberry
Directed by Joseph Pevney

If I had to list my favorite episodes of the original Star Trek series, there’s only a few episodes that I know for sure would be on the list. The Devil in the Dark is an episode that I know would be on the list. I could name this as a favorite without even having to think about it.

The Enterprise arrives on Janus VI, where a mining colony has been established. The miners have been plagued by a mysterious monster who seems to travel through solid rock like water and has been attacking men, burning them to death. Machinery has also been sabotaged by some type of corrosive agent. Right after the Enterprise arrives at the mining colony, a reactor pump is stolen, leaving the mining colony vulnerable to radiation as well as without any life support. If the pump is not returned, within 48 hours the mine will be uninhabitable.

This action leads Mr. Spock (Leonard Nimoy) to think that whatever else the creature is they are dealing with, it is intelligent. Based on silicon nodules found on the planet, Spock wonders if it is a life-form based on silicon rather than carbon.

Captain Kirk (William Shatner) and Mr. Spock dispatch a security team from the Enterprise to track the creature through the tunnels. One of the men is killed before he even gets the chance to fire his phaser, now calibrated for a silicon life-form. As they are studying a tunnel Spock has determined was created within the last hour, the creature shows itself.

The creature is known as a Horta. The way all of the information is learned is by Spock using the mind-meld, something that will become a staple throughout the series and the movies. Leonard Nimoy shows his acting ability as he convincingly sits next to a foam rubber blob and coveys a deep range of emotions. He makes me believe the Horta is real and makes the audience sympathize with its plight.

I’m a doctor, not a bricklayer!

The Devil in the Dark goes a long way with the character development of the big three in Star Trek. Dr. McCoy gets to be innovative and really shows his worth as a Starfleet doctor. It would have been easy to have him be a one-note character but he goes a long way to building his role with moments like these.

Kirk seems more on edge here, both with his crew and with the staff of the mining colony. With the miners, Kirk is terse and short. At first, it almost seems as if he doubts the miners’ story as they are under pressure to deliver the pergium. He seems impatient with Chief Engineer Vander berg (portrayed by Ken Lynch) right from the beginning, rather than waiting for the man to give him a reason to get on his nerves. During the episode, Shatner learned of the death of his father. Leonard Nimoy provided what was perhaps unintentional comic relief during that time with his performance as he mind-melds with the Horta. I do wonder if Nimoy intended the performance to be the one that would air, or if he intended it only to be for Shatner’s benefit. It’s become a legendary performance, regardless. Knowing this about the actors as well as their characters goes a long way to show the bond they have shared throughout the years.

Where the episode fails a bit is with the secondary characters. They are pretty much one-note characters with no depth. They are there to serve a purpose, but they also manage to evoke little sympathy for them or their plight. I didn’t mind seeing the Horta burn them up, especially after you learn the motivation behind it. They come off as little more than a lynch mob.

The Horta costume may not be the best effect or costume ever created. It’s really more reminiscent of the aliens created for Doctor Who. Still, it is a lot of fun and I found it didn’t distract me, even watching it all these years later. The effects are suitable for what happens as well, and there’s no need to dazzle me with impressive effects when there’s a story that’s strong like here.

If you’ve never watched Star Trek before, this is a great place to start. There’s a good group of episodes that are some of the best of the series at the end of the first season, and this is one of them.

Previous episode in the series (link): Star Trek: The Original Series: This Side of Paradise

Next episode in the series (link): Star Trek: The Original Series: Errand of Mercy