The City on the Edge of Forever (1967)

McCoy (DeForest Kelley) is accidentally injected with a drug that makes him delusional of his surroundings. Escaping from "assassins," he beams to a nearby planet where he leaps through a sentient time portal altering all of human history—Kirk (William Shatner) and his landing party are marooned without a future since the Enterprise no longer exists. Kirk and Spock (Leonard Nimoy) cross the portal's transom in an effort to locate the drugged out doctor. They arrive in 1930's America before McCoy shows up and over a period of days Kirk falls in love with a social worker named Edith Keeler (Joan Collins). Interfacing a crudely constructed machine with his tricorder, Spock learns that Edith is the focal moment in time and was saved from dying by McCoy. He tells an emotionally gutted Kirk that Edith must die in order to realign time.

As a teen, I first watched this on VHS tape with my buddy Erik at least seven times over a 48 hour period absolutely mesmerized by the moral dilemma facing Kirk. His thousand yard stare upon returning to the future coupled with "Let's get the hell out of here" is unforgettable. I still think it is the best episode of the original series though I probably could be persuaded that "The Menagerie" is tied. "The City on the Edge of Forever" was written by legendary (oh so cranky) writer Harlan Ellison and in the 2008 documentary Dreams With Sharp Teeth he offers a detailed look at how his original script differed from the filmed version.

Next up: "Assignment: Earth" that guest stars Gary Lansing and Teri Garr.