Michael Schneider has an article on “bubble” shows: shows that aren’t canceled yet but aren’t doing well enough to be assured of renewal.
The biggest question about any show that’s on the bubble is how it handles the last episode, which could be the very last episode. As Schneider notes, the producers of Life on Mars took an unusual approach: they actually asked the network to announce their cancellation right away, so they could go out with a real series finale. They could do that because their ratings were so bad that they had no real chance of renewal; ABC was just holding back on stating the obvious. But most bubble shows aren’t doing so badly that they can afford to just give up — if they were doing that badly, they would already have been pulled off the air. A typical bubble show is one whose ratings are low but showing signs of growth, or doing well with certain targeted groups, or doing a little better than whatever it replaced. In other words, a show where there’s a plausible reason to argue that it could improve.
In that situation, the writers not only don’t know if they will get picked up, but they have to concentrate on making sure the last batch of episodes gives the network a reason to pick them up. They can’t wrap up the show, because that would be admitting defeat, but they can’t even do an episode that feels too much like it could be a series finale, because that would make the episode kind of low-energy and closure-heavy, when what they need to get picked up is something that leaves the audience wanting more.
So a bubble show will often end the season with an episode or episodes that resolve nothing, or very little, but get them some attention. I’ve mentioned the Seinfeld episode “The Deal” before; Larry David wrote that when it was a classic bubble show (ratings not great, but with signs of hope for the future), and he wrote the biggest story he’d ever created for the show, something that the network had specifically requested; Jerry and Elaine repeatedly sleep together and end the episode as boyfriend and girlfriend. The episode would have been a very unsatisfying series finale, even though it seemed to “resolve” the Jerry/Elaine sexual tension; but the main point of it was to build the audience and get the network to see that the show still had life in it. And it worked.
For another example, Knight Rider, which seemed like a lock for cancellation, improved its ratings enough in its season finale that it might (I said might) not be the series finale. They did it by mostly forgetting about closure and just ending the season with a run of cheesy plots in the true Knight Rider tradition.
But some bubble shows will at least try to do an episode that could serve as the series finale if necessary. This usually doesn’t work out so great; the last episode of Veronica Mars didn’t fully work as an episode or a finale. I sometimes think that a show is better off in the long run just ignoring the whole series finale gambit and trying to go out with a good open-ended episode; once the show goes into reruns, nobody really cares how the show ended (and some marketers believe, or used to believe, that too much closure actually hurts a show in syndication) unless it’s a show with some kind of over-arching plot or mystery. If it is like that, then the bubble show needs to find some way to tie up as many loose ends as possible while also leaving stuff over for another season if they get one; not an easy thing, and it’s rarely been done in a fully satisfying way.