Nowadays, network TV shows in the United States (with the exception of news programs and daytime soap operas) usually have about 22 episodes per season, give or take one or two. But networks rarely have enough confidence in a new show to order all 22 at once. Typically, the first 13 episodes will be ordered, followed by the remaining 9 if ratings are high enough. These sets of episodes are referred to as the "Front 13" and "Back 9", with the latter term being more commonly used. The front 13 are often produced before any episodes are aired and before there can be any public feedback. If the creators are doubtful about the back 9 being ordered, the 13th episode often contains some kind of resolution so the audience isn't left hanging. Short-Runners often have 12 or 13 episodes produced, even if not all of them were aired.
For clarification, there are two elements to this Production Trope:
- It has to air at or near the start of the Channel's standard broadcast season, which automatically disqualifies the premiere season of a Midseason Replacement.
- Though the series started "on time", the Executives' original order did not cover the full season and/or the first half of the Season is self-contained compared to the second half (the halves need not be equal).
The length of the "season" does not matter; theoretically a cable channel whose seasons are 13-16 episodes can still have a show suffer this if the initial order was for only 8 episodes.note Also, this does not necessarily apply to only the first season; a show that is Only Barely Renewed can also qualify, provided that the two halves of the season were separate orders or the production crew had reason to believe that they would be told to Wrap It Up before May.
The most obvious signs of this Trope in a series that gets to/past (e.g.) the February Sweeps (apart from Word of God) are the additions or alterations of important elements or a change in show atmosphere midway through the first Season (as opposed to between the first and second seasons) or a Series Fauxnale in the middle of any season.
Compare 12-Episode Anime and British Brevity, the latter of which denotes a country with a short broadcast season. Contrast Cut Short, where a series doesn't even make the full Front 13 or only makes 13 when it had been promised more.
- 24 has Bauer's wife and daughter rescued and the first assassin killed in the 13th episode, providing some resolution if the back 11note was not ordered. The scene where the second assassin was dispatched could have been cut in that case.
- The 13th episode of Arrested Development draws a number of its initial plot arcs to a close, including the Love Triangle between Michael, Marta, and Gob, as well as Tobias' anxiety over going nude.
- The 13th episode of Brooklyn Nine-Nine resolved most of its plot arcs at the time, giving us the result of the bet and the fallout of Boyle's heroic feat.
- Season 1 of Chowder was originally 13 half hours before being expanded to 20, resulting in the redesigns planned for season 2 to be implemented within season 1.
- Chuck: The show was renewed for a third season with an original order of 13 episodes only for the network to order another 6 episodes just after the crew had finished the intended "finale". The writers were forced to scramble and come up with a short arc to fill out the season. The network then proceeded to do the exact same thing with the fourth season, this time ordering a further eleven episodes.
- In Community, there is a very clear shift in tone and characterization after the first half of the first season that persisted for the rest of the show's run, making the first half come off as particularly rough.
- There's an urban legend that Fox Kids purchased an alternate ending to the 13th episode of the Digimon Adventure dub, just in case the show didn't do well on their air. That would explain a lot of its Early-Installment Weirdness quite handily, though it has never been proven to have actually happened.
- Though its first half was as a Midseason Replacement, Dollhouse's second season qualifies. FOX made the 13-episode order primarily due to fan response; the execs, in turn, excluded the series from the November Sweeps, though at least they ran the complete half-order this time.
- In Fringe the 13th episode of the first season, "The Transformation", resolves the John Scott arc, and Mark Valley never appears again. The next episode, "Ability", starts the examination of the Olivia's Cortexiphan-related talents.
- Glee had a crucial competition win, resolution for several story arcs, and even a traditional kiss in the final scene in its 13th episode, and could easily be considered a satisfying series finale. All of the front 13 were produced before airing and have fewer songs. They're also generally considered the show's best episodes by the majority of the fandom.
- Infinity Train was initially greenlight as a 10-episode Mini Series before the order was expanded to a full season of 20 episodes. By that point, the writers had already finished writing Tulip's story arc and had no desire to stretch it out; their solution was to turn the show into a genre anthology, and make the additional episodes a new storyline about Tulip's Mirror Self.
- Anime example: David Production's adaptation of JoJo's Bizarre Adventure has an inverted case in its first season. The "Phantom Blood" story ends precisely and cleanly at the end of its 9th episode, leaving the rest of its first season to adapt the next part, "Battle Tendency."
- The second season of Lucifer was greenlit with 13 episodes, then received an additional 9-episode order a month after the season started (though four of them ended up being moved to the third season). The 13th episode, "A Good Day to Die", has a very climactic season finale feel in it, representing a break between the first half of the season with the second. There is even a Time Skip between the two.
- The Mob Doctor is an example from the 2012 Fall Lineup: 13 Episodes ordered for September, Cut at the end of its initial run in January.
- A visitor to the Best Brains offices during the production of the last few episodes of Mystery Science Theater 3000 reported seeing a note that said something like "Wish List: Season 11. Season 10, back nine. A job." The first two entries were crossed out.
- The Parks and Recreation season 5 episode, "Leslie and Ben" was the 13th episode produced (but the 14th episode shown due to "Women in Garbage", one of the back 9, being aired Out of Order), and as such, was written as a respectable finale for the show, which has always had low ratings and shaky renewals.
- The final season of Person of Interest was only 13 episodes long. The production crew knew they weren't going to get approval for the back nine, so they wrapped up all the remaining major plot threads in those 13 episodes.
- The 2nd season of Star vs. the Forces of Evil follows this format with the first 13 half hours (My New Wand! to Bon Bon the Birthday Clown) ending on a Wham Episode, the following 8 half hours (Raid the Cave to Starcrushed) following the consequences of said episode, and a half hour of standalone episodes that fall in between in production order (Hungry Larry and Spider with a Top Hat) being deliberately written to be able to premier whenever in the season and still fit given the former's Holiday episode status.
- Steven Universe's first season was originally 26 quarter-hour episodes, but the show's success lead to them expanding it to 52.note The twenty-sixth episode ended on a series of reveals about Steven's guardians and had him successfully control his powers for the first time. Word of God says that Garnet and Pearl's conversation was originally going to be more conclusive as well, but the extension came soon enough that it was changed to be more of a hook hinting towards the invasion plotline that the second half of the season would tackle.
- Inverted in the case of Vanished: an initial 22 episode order was cut to 13 after 6 episodes had aired.