"The Man Trap" - The Original Series Season 1, Episode 1
(please note that full episode summaries are best found on Memory Alpha, and will be linked to in each headline)
Kirk, McCoy, and another crewman beam down to a planet staffed by an archaeologist married to McCoy's old girlfriend, only to find she's been supplanted by a creature that consumes salt. The creature, who can take human form, goes on to attack and murder several before being defeated.
This episode is our first introduction to a standard The Original Series trope: the alien murderer of the week. Kirk and crew very often come up against a murderous non-humanoid who has some sort of defense system they have to penetrate, before defeating them. In this case, it causes a moral dilemma for McCoy, as the creature has taken the guise of his ex-girlfriend, though, admittedly, not a particularly strong dilemma.
The adventure is very quickly revealed to the audience, leading to little mystery surrounding this particular alien murderer. Instead, the suspense comes from us watching Kirk's efforts to grapple with what he is facing, and then the crew's attempt to locate the dangerous shapeshifter once it has come aboard the Enterprise. At one point, the creature replaces Bones and takes his place in a meeting where the senior staff discuss how they will best hunt down the alien, leading to the final murder of the episode and an attack on Spock. The tension of this storyline is very well written, and the episode is very enjoyable as a result.
We learn a lot about Kirk in this episode. He is brash, headstrong, and even a little rude. He doesn't like mysteries, and isn't opposed to using his power and strength to brute force through a situation. Kirk will tear down and destroy in order to fix if he feels he needs to, which gives him the sort of edge that the rough-and-tumble captain of the Enterprise requires. Kirk bullies the archaeologist, Dr. Crater, thoroughly, in places, going so far as to deny Dr. Crater his simple request of extra salt tablets. Things aren't right, and Kirk declares, "But it's a mystery. And I don't like mysteries. They give me a bellyache. And I've got a beauty right now."
Yet, at the end, Kirk is shown to have a softer side. Although he was adamant in the need to defeat the salt-sucking alien to protect his crew, and showed little remorse at the death of Dr. Crater, he did reminisce quietly at the end. Though in self-defense, the crew of the Enterprise had slain the last member of a sentient species. He confesses to Spock that he was remembering the plight of Earth's buffalo.
Similarly, McCoy is shown to be cautious, nostalgic, and very much in touch with his past. He pines, secretly, for his old love and an easier time. He is xenophobic to an extent, and the famous rivalry with Spock begins immediately. Spock, of course, is set up to be impassionate, reacting not-at-all when the death of an away team member is announced, to the chagrin of those on the bridge. He does not understand Uhura's attempts to make small talk, and he certainly does not appreciate the passion with which McCoy views his lost love. He uses logic in the most desperate of situations, striking the creature that has fooled McCoy, until he realizes that the object of his desire is not, in fact, real.
"The Man Trap" continues to deliver with introducing us to the bread-and-butter of what will be The Original Series, with the unfortunate death of four ensigns during the making of this episodes, all victims of the salt-sucking alien. Known as "redshirts" (though not all of the dead ensigns wear red uniforms in this episode), these expendable crewmen will continue to die over the course of the series, and are used to create tension within the episode. By the end of the series, I am sure it will seem almost ludicrous, but that's part of the charm of The Original Series. It doesn't take itself too seriously.
Overall, "The Man Trap" delivers a great introduction to The Original Series and lays out some very important points for our three main crew members. We're introduced to Uhura and Sulu, as well as Yeoman Janice Rand, but none of these three characters are heavily developed at this point. The series focuses on Kirk, Spock, and McCoy, the three men who will carry the series in most episodes, and we can assume the others will receive some development over time. The story is not a great human interest piece, but more of a sci-fi thriller, a style of episode that shouldn't be underestimated in its ability to provide enjoyment.
Characters: 8/10 - great character development for the introduction of three new characters.
Story: 7/10 - a good "alien murderer of the week" plot that is still fresh.
Star Trek factor: 5/10 - there is a moral dilemma, but one that is easily solved by the standards that will develop as the series continues.
Overall: 7/10 - a fine episode of The Original Series, but not one that leaps out as either a landmark episode or a giant piece of crap.