It's very good, but is it the best Star Trek episode ever? No. Although your opinion may differ. (For what it's worth I'm aware of the complicated background to the episode and the arguments down the years about the rewriting of Harlan Ellison's script by then story editor Steven W. Carabatsos, Gene L. Coon, D.C. Fontana, and Gene Roddenberry. I'm just not going there. As with The Alternative Factor what counts is what appears on screen; and hopefully that's the only time The Alternative Factor gets grouped with The City On The Edge Of Forever)
The central weakness of the episode is Edith Keeler. There's frequently a heavy handedness to the way her character is written as if whoever put the final draft together felt that the woman Captain Kirk fell in love with had to be more than extraordinary. It's not enough for her to run a soup-kitchen and be be kind and generous and compassionate. Edith is also written as if she had a direct line to the future. At the Twenty-First Street Mission she gives a speech after the evening meal. “Now I don't pretend to tell you how to find happiness and love when every day is just a struggle to survive, but I do insist that you do survive because the days and the years ahead are worth living for. One day soon man is going to be able to harness incredible energies, maybe even the atom. Energies that could ultimately hurl us to other worlds in some sort of spaceship. And the men that reach out into space will be able to find ways to feed the hungry millions of the world and to cure their diseases. They will be able to find a way to give each man hope and a common future, and those are the days worth living for. Our deserts will bloom.”
When Spock and Leila fall in love in This Side Of Paradise the relationship works precisely because it is not presented to us as The Romance Of The Century. They are simply two people who make each other happy. By contrast Edith's speech above is just unsubtle, and obvious. It's the same problem which affects The Corbomite Maneuver and Court Martial the need to compress maximum information into the minimum amount of time. In those two episodes the result was Navigator Bailey the universe's most incompetent bridge officer, and rambling madman Ben Finney. In The City On The Edge Of Forever the script beats the audience over the head with Edith's qualities. The audience is supposed to be surprised Kirk falls in love with Keeler, after that speech it would be more surprising if he didn't.
Another weakness with the speech is the way it is played. Either Joan Collins, or Joseph Pevney the director, has decided the speech should be played with hesitancy. A literal transcription of the speech would look like this. “One day.. soon... man.. is going to be able to harness.. incredible energies... maybe even the atom.... Energies that could ultimately hurl us to other worlds in... in.. some sort of spaceship... And the men that reach out into space will be able to find WAYS! to feed the hungry millions of the world and to cure their diseases.” The effect of playing that speech with pauses is to make it sound as if she is making it up on the spur of the moment. Yet one of the other people using the mission tells Kirk, and the audience, that listening to Edith talk is how they always pay for their meal. The intent of the speech, that Kirk should be captivated by Edith's rock-solid belief in a better future, and the delivery, hesitant and uncertain, undercut each other. It looks like Kirk falls in love with her because she talks about atomic power and spaceships. It gives the impression he'd have fallen in love with any science-fiction writer.
To be fair, the writing for Keeler is a lot sharper elsewhere in the script, such as the exchange when she first meets Kirk, and Spock, who have snuck into the mission basement.
KIRK: Excuse us, miss. We didn't mean to trespass. It's cold outside.
EDITH: A lie is a poor way to say hello. It isn't that cold.
That's how you write a character who is intelligent and not afraid to stand up for themselves. That's a believable character for Kirk to fall in love with, someone who isn't afraid to challenge his poor behaviour when they first meet. The same is true later in the episode when it's made clear Kirk and Edith share a core philosophy.
EDITH:... I think that one day they'll take all the money they spend now on war and death
KIRK: And make them spend it on life?
EDITH: Yes. You see the same things that I do. We speak the same language.
Unfortunately for William Shatner and Joan Collins This Side Of Paradise has already set the bar for romance in Star Trek. Both Shatner and Collins are charismatic and likeable, but neither of them are able to act at the same level as Leonard Nimoy and Jill Ireland. The City On The Edge Of Forever has no equivalent of the transporter room scene where Leila realises she has lost Spock for a second time. When Shatner and Collins have the screen to themselves they never capture that same intensity. The friendship between Kirk and Spock, and the joy when Kirk and Spock are reunited with McCoy, are more convincing and better played. However, having said that, there is a lovely moment, both scripted and acted, as Spock and Kirk review Edith's potential future.
KIRK: The President and Edith Keeler.
KIRK: The President and Edith Keeler.
SPOCK: It would seem unlikely, Jim. A few moments ago, I read a 1930 newspaper article.
KIRK: We know her future. Within six years from now, she'll become very important. Nationally famous
Shatner perfectly captures Kirk's pride at the idea of Edith meeting FDR. As if he believes history itself is giving her a stamp of approval and validating all those qualities he sees in her.
There's also a pleasing attention to detail with the other characters. Just before using the Guardian Kirk orders Scotty, “when you think you've waited long enough. Each of you will have to try it. Even if you fail, at least you'll be alive in some past world somewhere.” It's a small moment but by showing us Kirk thinking about his crew it brings the characters to life. As do exchanges like this one.
MCCOY: Some heart flutter. Better risk a few drops of cordrazine.
KIRK: Tricky stuff. Are you sure you want to risk [The hypo hisses and Sulu opens his eyes.]
MCCOY: You were about to make a medical comment, Jim?
KIRK: Who, me, Doctor?
And for a script which is so unsubtle about Edith Keeler, there's a delicacy to the way it introduces the audience to the idea of using the Guardian to travel in time, and alter the past. Right before McCoy escapes into history Kirk asks Spock if they could take McCoy back to the day before and avoid the accidental overdoes of cordrazine. That one line, and Spock's reply about the difficulty of stepping through on a specific day seeds the audience with the idea that the Guardian can be used to travel in time, and alter history, and that it is a difficult and dangerous process.
What also surprises about the script is the pacing. Edith Keeler's big introductory speech takes place 22 minutes into a 48 minute episode. This is a story packed with incident and yet the episode never feels rushed. McCoy accidentally overdoses on cordrazine and goes insane. A mysterious artefact allows travel into the past (and presumably the future). History must be restored to the correct path. Adventures in 1930s New York. Kirk falls in love. Another writer could have built an entire script just from the idea of a race against time manhunt for a temporarily insane McCoy on the surface of a dead planet. There is almost enough material in here for two or three separate episodes. This is a common factor with several of the better episodes of Star Trek: The Corbomite Manouver, Arena, This Side Of Paradise, The Devil In The Dark. It's not exclusively true. Some good stories are quite spartan in comparison, Balance Of Terror for example, but it often does seem to be a common factor that good stories pack in material. By contrast disappointing stories like The Alternative Factor or The Return Of The Archons tend to overextend a single idea. The Alternative Factor mainly involves Kirk getting more and more annoyed with Lazarus, until he realises Lazarus is two separate people, and blows up their spaceship trapping the pair forever.
Once again Joseph Peveny puts in solid work as director. Location filming on the Desilu backlot, seen in Miri and The Return Of The Archons, uses tight camera angles, clever use of extras, and period vehicles to bring the streets to life. All this background detail came at a cost, the total budget for this episode was $245,316, compared to the series average of around $190,000. Look at the tracking shot as Kirk and Spock run away from the Policeman, there are a lot of extras on set. Plus, some simple but effective use of sound effects with the noise of a dog barking. Edith's death is well staged. It's filmed at night and nicely foreshadowed when Kirk and Edith head off to the cinema. As they step into the road a car screeches to a halt and Kirk pulls Edith back.
Film editor James D. Ballas puts together an effective sequence for Edith's date with destiny. An unusual optical zoom is used to pull sharply into Kirk's shocked face, and Edith's as she walks across the road. The choice of shots is also interesting. The obvious way to play the sequence would be to concentrate on Shatner's face, and have him react to off screen noises; a squeal of breaks, a thump, and maybe shouts of alarm. Instead Peveny, or Ballas, goes for the opposite approach. As Kirk holds McCoy he faces away from the camera, it's McCoy's reactions which tell us what is happening, and then we cut to a wider shot showing Edith dead in the road with people running to help. We don't see Kirk's face until the accident is completely over, when the enormity of what he has done has sunk in. Even when he releases McCoy, Kirk never looks round at Edith's body. Kirk walks towards a wall and leans on it, still not looking round, and we fade to the Guardian's planet, and then Kirk, Spock, and McCoy returning. There is lovely passage of time in those three shots. The audience never finds out how long it has been since the accident, although Kirk and Spock have had time to change out of the civilian clothes they wore in 1930s New York. There's very little dialogue, there doesn't need to be. Kirk's silence, and final line, tells us all we need to know.
Enterprise crew deaths: None, again.
Running total: 26