City on the Edge of Forever
After a medical accident, McCoy leaps into a time portal and alters Earth history. Kirk and Spock must restore the past, though it means incredible sacrifice.
In agreement with most fans and science fiction authorities, we'll call this the best episode of TOS. (Our personal favorite is Amok Time, but that's the Spock bias kicking in.) Anyway, the moral dilemma here cuts deep, and there is a good balance of humourous moments to serious. Who can forget the mechanical rice picker, the mnemonic circuit, Spock in jeans and a toque? The '30s setting is completely works, with all the grit accounted for. The Guardian is an interesting character, offering great possibilities but also great dangers. McCoy provides one. Kelley gives a great performance, convincing us fully that our good doctor is deranged. Kirk, meanwhile, is love struck. His relationship with Edith develops slowly and naturally, remarkably so considering the running time. Spock must play devil's advocate again, convincing Kirk one must die so millions might live. In Star Trek, the butterfly effect (that is, any tiny change in history having huge repercussions) is not a worry, but removing a person or changing when, where, or whether they die results in considerable (and negative) change. Still, the gang is always at its best when out of their time, and this is no exception.
Spock Saves the Day: Spock records the passage of time with his tricorder, determines when to jump through the portal, and recovers information essential to restoring the flow of human history to its proper course.
Oops: Putting the toque on right away would have been wise, but then we wouldn't get to see Kirk squirm.
Developments: This is generally a landmark episode, but there is little growth and change on Spock's part. Again he - with good reason - insists on the death of someone Jim likes (re: Charlie X and Where No Man Has Gone Before), plus he stays at Jim's side and teases him. (see: every episode.) His only new skill is mechanical, constructing a massive device compatible with 23rd century technology from crude supplies. Since Spock's main function here is to play the rational foil to the emotion-driven Kirk and McCoy, he stays true to type.