These days, most successful TV shows have very serialized storylines. Generally, this makes it more exciting for the audience as they become engaged in a plot line that spans the course of one or more seasons. I enjoy many of these shows. In fact, my favorite show that is currently airing is 'Marvel’s Agents of Shield'.
However, it seems that TV shows that have standalone episodes week to week has become a lost art. The disadvantage of serialized TV, is, when you want to go back and watch a random episode, you might be lost (even if it does have a “previously on…” segment before the episode).
So how does this fit into Star Trek?
Undoubtedly, Deep Space Nine did more serialized storytelling than any of the other Trek shows. DS9 became an excellent show, and was different from the Star Trek series that came before it (in ways that were necessary to keep the franchise fresh & interesting). But, if you take somebody who has never seen DS9, and show them “In the Pale Moonlight” (considered by many fans to be the best DS9 episode), they may enjoy it, but it won’t have nearly the same impact that it does on those who are caught up on the serialized storyline.
Voyager’s storyline is serialized in that the entire series revolves around the crew’s attempts to return home. There are some other serialized storylines (early episodes with Seska and the Kazon come to mind), but, for the most part, you can pick a random episode from any season and watch it without being lost.
Enterprise was lightly serialized in the first 2 seasons. These lightly serialized storylines were mostly relative to the Temporal Cold War. The 3rd season took a completely different turn, with a season-long serialized storyline. The 4th and final season consisted mostly of 2 and 3 episode story arcs, and is considered by most fans to be the best of the 4 seasons.
By nature, Star Trek: The Next Generation was not a serialized TV show. In fact, I’d argue that TNG mastered the art of telling engaging “one-off” stories better than any show that came before or after. There was a general mandate that the writers avoid any serialized storytelling. Everything needed to be wrapped up by the end of the episode. Therefore, one can watch almost any episode from any season without being lost.
But diehard fans of TNG know that there is serialized storytelling within TNG. It was done masterfully. Fans who paid close attention were aware of it, but it didn’t take away from the ability to watch any episode from any season at any time.
The Borg were referenced as early as Season 1 (although not by name) when planets near the Neutral Zone are found to have civilizations that appear to have been “scooped” off the planet.
Tasha Yar’s reappearance in Season 3’s “Yesterday’s Enterprise” acts as a “do-over” of sorts for the pointless death the character was given in the first season. In the alternate universe of “Yesterday’s Enterprise”, Tasha goes back in time with the Enterprise C to finish a hopeless battle against the Romulans.
In Seasons 4 & 5, a new Romulan villain appears that bears a striking resemblance to Tasha Yar. It turns out that Tasha didn’t die in battle with the Romulans after all. This Romulan Villan, Sela, is the daughter of Tasha Yar and a Romulan. Apparently, when the Enterprise C returned to its own time (restoring the TNG timeline for our characters in “Yesterday’s Enterprise”), Tasha was captured, not killed. She was forced to have a child with a Romulan, and was later killed when trying to escape with a young Sela.
In Season 3’s “Sins of the Father” Worf decides to go along with a lie (that his father was a traitor) - and the dishonor that comes with that lie - to keep the Klingon empire intact. This is a great irony in that Worf has accepted dishonor to save a Klingon empire that supposedly holds honor above all else. This extremely honorable, selfless act, makes Worf even more of an outcast in the eyes of most other Klingons. When this episode aired, there was no doubt that this plot line would need to be revisited.
Many of the episodes that followed referenced Worf’s dishonor, and in the Season 4 cliffhanger, “Redemption,” Worf’s honor and family name were finally restored. Much of what we currently know about Klingons came from TNG, and episodes concerning Klingon culture, politics, and religion occurred during the course of the series.
Many fans agree that the Season 3 cliffhanger, “The Best of Both Worlds”, is the best cliffhanger in Star Trek history. Captain Picard had been abducted by the Borg, forced to participate in the deaths of thousands of Starfleet officers, and, by the end of the 2-part story, he had been rescued. He was human again, but the emotional scars ran very deep. Some Trek episodes are at fault of putting characters through traumatic experiences, only to have them back to status quo by the next week. The writers and producers of TNG knew that, after what happened to Picard, they couldn’t simply do this. Therefore, Season 4’s conclusion to “The Best of Both” worlds was followed by the episode “Family" - in which Picard visits family on earth, considers leaving Starfleet, and ultimately breaks into tears over what the Borg had done to him.
There are many more examples of these lightly serialized threads throughout the series. The point is that the series was able to balance these serialized story threads within the weekly “one-off” episodes that didn’t alienate viewers that had not seen the preceding episodes. This is one of the many reasons that 'Star Trek: The Next Generation' is my favorite TV show.
One last episode that deserves to be mentioned is the outstanding series finale, “All Good Things” that brought back the fan-favorte character Q, and had Captain Picard shifting through three time periods - one of which occurs just before, and during, the events of the pilot episode.