Un Installment

"Strong Sad: So wait. Was there ever a "Jibblies 1"? Strong Bad: Nah, horror movies don't even need first movies anymore."

- Homestar Runner, "Jibblies 2"

An ongoing series deliberately skips an installment number. Events from the missing installment may be referred to as if they had actually happened; there may even be an assurance that it was the highlight of the series.

Reasons for doing this include:


 * Some form of numerological significance, such as avoiding the number 13 or the number 4
 * To acknowledge a long hiatus between installments
 * To get out of having written oneself into a corner, by pretending that it's already been solved, somehow, when nobody was looking
 * Because it would be impossible to do the events of the phantom installment justice
 * To set up a mystery about the events of the missing installment

When the non-existent episode is treated by subsequent episodes as if it existed, related to Second Hand Storytelling and perhaps to Noodle Incident.

A related trick is to bring out a new work that claims to have been made years ago and then shelved or forgotten; we don't seem to have a trope page for that, but Garth Marenghi's Darkplace is an example, and it's related to Retraux.

When there's supposedly an entire series of non-existent episodes preceding the first that actually exists, it's Retroactive Legacy.

See also Oddly-Named Sequel 2: Electric Boogaloo, where a sequel might be given a strange numbering (such as The Naked Gun 33⅓ or Halloween H20) without meaning to imply a missing installment; and Unusual Chapter Numbers. Also Stopped Numbering Sequels which may predate Un Installment.

Anime and Manga

 * The original Kujibiki Unbalance probably has the highest ratio of Un Installment episodes to real episodes: out of the 26-episode series, only three episodes (1, 21, and 25) were actually made, though episode 21 happens to be a Recap Episode. The episodes were released as bonus material on the DVDs of Genshiken, to which it is a Show Within a Show.
 * Devil Hunter Yohko has no episode 4, because Four Is Death. (In the US, ADV Films filled the gap with a collection of music videos it called "Devil Hunter Yohko 4 Ever".)
 * Episode 12 of Excel Saga is called "Big City, Part II". There is no Big City, Part I, as Excel explains in the preview for episode 12.

Comic Books

 * Gaston Lagaffe notoriously has no volume 5, because the comic switched to the A4 format from volume 6 onwards and the first four A4 volumes are compilations from small-format books.
 * DC Comics' Ambush Bug: Year None ended with "issue number 7 of a 6-issue limited series." There is no issue number 6, or at least none that was ever published. Apparently number 6 was completed (or nearly so), then shelved for reasons that still have not been made entirely clear. Number 7 came out many months later, wrapping up the series.
 * Back when they were at Image Comics, Wildstorm and Rob Liefeld's Extreme Studios reversed this with a quasi-cross over event where they published their 25th issues months ahead of time to give a glimpse of the future and continued their series the next month. Several of the involved series never made it as far as #25, leaving the missing issues as uninstallments.
 * Captain Marvel first appeared in two ashcan comics titled Flash Comics #1 and Thunder Comics #1. Then his regular title, Whiz Comics, began with issue #2, and reprinted the whole of both ashcans. There is no Whiz Comics #1.
 * Spawn once skipped a few issues because the series was behind on deadlines. Fans were not happy so replacement issues were published later.

Film

 * The third movie in Robert Rodriguez's Mariachi Tetralogy. Basically, a fair number of people who saw Desperado didn't immediately realize that it was a sequel, until they realized they were missing backstory that the film kept referring and flashing back to. As a nod to this, Robert Rodriguez came up with an entire third installment that follows up Desperado, introduces new characters, has very major plot developments, and was promptly never produced. Once Upon a Time In Mexico is the sequel to that film, and throws in a lot of references to the plot and events of that film, which are central to El Mariachi's own character arc in the final film.
 * Surf II. There never was a Surf I.
 * Perhaps not exactly this, but definitely related, the "missing" reels in Grindhouse.
 * The Opening Scroll of Spaceballs identifies the events of the movie as "Chapter Eleven" of a saga (another riff on Star Wars, which started with Episode IV).
 * In addition, one of the film's main characters, Yogurt, says "God willing, we'll all meet again in Spaceballs 2: The Search for More Money," fooling people into believing that a sequel is in production.
 * A sequel was planned, but never made. It was called Spaceballs 3: The Search for Spaceballs 2
 * Zombi 2: Lucio Fulci's film based on a zombie epidemic on a tropical island. Despite its title implying that it is a sequel to another film, it's actually a standalone movie with no relation to any previous zombie films. The confusion comes from the fact that George A. Romero's Dawn of the Dead was renamed Zombi in Italy. Fulci's film was only named Zombi 2 to cash in on the success of Romero's film, even though there's no connection between the two.
 * The Executioner, Part II.

Literature
"German censors - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - idiots - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -"
 * The Great Samuel Pepys Fiasco is a missing book in Jasper Fforde's Thursday Next series. Because it's all about the world where fiction is created, there's a very good in-story explanation for why it's missing.
 * Sideways Stories from Wayside School has no nineteenth chapter, because the builders forgot to build a nineteenth story.
 * Volume 4 of Tristram Shandy has no chapter 24. Chapter 25 helpfully starts by describing what would have been in chapter 24, if it had existed.
 * Theodor Mommsen's Roman History, which won him the Nobel Prize for Literature in 1902, consists of volumes 1, 2, 3 and 5. The first three describe the history of the Roman Republic and were published during Mommsen's lifetime. Volume 4, the history of Imperial Rome, was never finished (it was sort of replaced - in 1992! - by Mommsen's lectures on the subject, not from manuscripts of his own, but as they were written down by students). Volume 5 contains the history of the Roman provinces during the Imperial era.
 * Alexander Pushkin's Yevgeny Onegin consists of numbered stanzas within each of its eight chapters, but some of these stanzas are left blank, e. g. Nos. 9, 13, 14, 39, 40 and 41 in the first chapter.
 * Chapter 11 of Heinrich Heine's book Ideen - Das Buch Le Grand ("Ideas - The Book Le Grand") reads thusly:


 * The Kurt Vonnegut novel Timequake probably qualifies. In-story, time ran backwards for several years, then played back out again. Vonnegut makes frequent references to a previous version of Timequake he wrote during this temporal slip, which he refers to as Timequake One, and that doesn't exist.

Live Action TV

 * Red Dwarf: Series VIII was followed by a ten-year hiatus and then by a one-off special, Back to Earth, which claimed to be set after Series X and referred to several significant events from the two skipped seasons. Done partly to acknowledge the hiatus and partly because Series VIII ended in a way that would have been awkward to follow immediately on from.
 * Power Rangers has "Scorpion Rain" which straddles the line between this, Urban Legend of Zelda, and Ascended Fanon. A supposed 8 minute short that bridged Power Rangers Zeo and "Turbo: A Power Rangers Movie", released only in Australia, the thing was supposed to be incredibly poorly done, but would fill in enough plot holes that the fandom went along with it. Eventually though, it was revealed as an elaborate prank. Later, in the Crossover "Forever Red", events of the battle "Scorpion Rain" supposedly depicted were referenced. Writer Amit Bhaumik, also one of the pranksters, admitted that he set out to make the darn thing canon.

Music

 * The Traveling Wilburys' first album was titled The Traveling Wilburys Volume One as a joke, because they were never going to do a Volume Two. When they did release a follow-up, it was titled The Traveling Wilburys Volume Three.
 * Chickenfoot pulled a similar joke when they called their second album Chickenfoot III.
 * Calexico's The Black Light has a song called "The Ride, Pt II". There is no Part I. Similarly, Hot Rail has "Untitled III" and "Untitled II" (in that order), but no "Untitled I".
 * Beastie Boys: There is no Hot Sauce Committee Part One. At least, not now.
 * Alien Ant Farm's debut album was titled "Greatest Hits," implying to be a compilation of earlier albums that don't exist.
 * After an eight-year gap, the band Boston finally released their third album in 1986. They joked in interviews that to speed things along, they were going to skip their fourth album and go straight to the fifth. (It didn't work; their next album took another eight years.)

Other

 * There was no 1983 Corvette. This is especially odd, as it was the model's 30th anniversary year. (Technically there were forty-four '83 prototypes, of which 43 were destroyed. The last is in the Corvette Museum.)

Radio

 * On Round the Horne, one of the show's spoof dramas jumped from part one to part three, with the explanation that "you wouldn't have liked part two - it was all plot." On another occasion, a Three Musketeers spoof stretched over two shows; in the show after that, it was announced "At this point we were going to do The Three Musketeers part three... But we got fed up with that."

Software

 * Microsoft's first version of Windows NT (which currently forms the basis of all desktop, workstation, and server versions of Windows as of Windows XP and Windows Server 2003, with the NT branding dropped with the earlier Windows 2000) was given the version 3.1 to match the version number of the then-current DOS-based version of Windows, which was also numbered 3.1. Unlike the DOS-based versions, there were no 1.x, 2.x, or 3.0 versions of it.
 * Partially justified in that Windows NT was a sequel to Microsoft/IBM OS/2, which had 1.x and 2.x versions. A lot of early marketing and technical information about Windows NT 3.1 indicated this, although as Microsoft moved away from the OS/2 name (IBM having continued development on its own branch) the ties became less visible as time went on.
 * Internally, Microsoft's Office 2007 is known as version 12, while the 2010 version is known as version 14, due to that number.
 * Winamp 3 was criticized by users for being buggier and more resource hungry than the 2.x series, and for missing features such as backwards compatibility with Winamp 2 skins. The next version, Winamp 5, was named to signify the fact that it was based off the 2.0 version and incorporated features from the 3.0 version (such as the new skinning system), and because they did not want people making Winamp 4 skins.
 * When Netscape released the codebase of Navigator 4, the intent was that community-made improvements would be rolled into version 5. However, the code turned out to be too difficult to work with, leading to a complete rewrite and using the new Mozilla codebase as the underpinnings of Netscape 6.
 * To synchronize the version numbers of Firefox and Thunderbird (which previously had the latter being given lower version numbers), Mozilla completely skipped version 4.0 of the latter and released version 5.0 of it around the same time as version 5.0 of the former (which did have a version 4.0 when Thunderbird was still at version 3). Currently, both programs still follow a similar numbering system.

Sports

 * Whenever Olympic Games didn't take place (in 1916, 1940 and 1944 due to the two World Wars), their ordinal number was skipped as if they had taken place.
 * Technically, it's "The Games of the Nth Olympiad". The four-year periods called Olympiads continue to be counted, whether or not the Games take place.
 * The first time the German football (soccer to Americans) championship was held in 1903, one of the semi-finals was DSC Prague vs. Karlsruhe FV. The Karlsruhe club received a fake telegram that the match had been postponed and did not show up, and Prague went on to the final (where it lost to Vf B Leipzig) by default. The following year, the final was going to be held in Berlin, but because it involved Britannia Berlin, Karlsruhe FV protested that this was not on neutral ground. The protest was successful, but resulted not in the final being adjourned to another city, but being canceled. Therefore 1904 there was no German football champion.

Tabletop Games

 * Paranoia has had (in order) 1st edition, 2nd edition, 5th edition (later declared an "unproduct", and 3rd edition (unpublished). Starting with the revival, they Stopped Numbering Sequels, instead releasing XP (formally dropped after Microsoft complained, so this version was just called "Paranoia") and 25th Anniversary Edition (a reprint of XP with some additional material).
 * The one-off Magic: The Gathering set Coldsnap is an example of the aforementioned trick where a new work is presented as a forgotten older one. Originally, the Ice Age block (released in 1995-96) consisted of Ice Age, Alliances, and the unrelated and universally reviled set Homelands, which was shoehorned into the block (mainly because this was before Wizards started doing blocks like we would know them today). When Coldsnap, which was designed to fit retroactively into Ice Age block as the "real" third set, was announced in 2006, Wizards claimed that it was based on a lost design file from 1995, uncovered when they moved their offices across the street. (The claim was intended to be tongue-in-cheek, but this didn't really come across and many players became annoyed, forcing them to come clean.) The idea of Coldsnap as the "real" third set, however, is Canon; it is legal for play in Ice Age Block Constructed, and Homelands is no longer acknowledged as part of the block.

Video Games

 * Al Lowe envisioned Leisure Suit Larry 3: Passionate Patti in Pursuit of the Pulsating Pectorals as the definitive end to the Larry trilogy, and the game ended with Larry and Patti stuck in the real world, living happily together and coding adventure games based on Larry's adventures. Whenever anyone would ask if his next project would be Larry 4, he would respond that there would never be a Larry 4. Instead, he and the rest of Sierra focused their efforts on creating a new online platform, which eventually fell through. However, when the time came for Al Lowe to make a real sequel to Larry 3, he found he'd written himself into a creative corner with Larry 3's airtight ending, so he decided to stay true to his promise and skipped right to Leisure Suit Larry 5: Passionate Patti Does a Little Undercover Work, where Larry and Patti are separated again, and suffering from amnesia. The missing game eventually becomes a major plot point in Larry 5, where it's revealed that . The game's non-existence is a running joke in the series, and the game (under the title Leisure Suit Larry 4: The Missing Floppies) appears in Space Quest IV and Leisure Suit Larry: Magna Cum Laude.
 * Tales of Monkey Island doesn't follow on directly from Escape from Monkey Island, but instead from a non-existent (and reportedly "epic") fifth Monkey Island game, presumably as a nod to the previous game where some characters refer to their "five-game contract" with Lucas Arts.
 * Ogre Battle March of the Black Queen serves as Episode V of what is officially known as the "Ogre Battle Saga", while Tactics Ogre (the second game) is Episode VII and Ogre Battle 64 (the third game) is Episode VI. Ogre Battle: Legend of the Zenobia Prince for the Neo Geo Pocket and Tactics Ogre: Knight of Lodus for the Game Boy Advance are considered side-stories, despite both being just as long and complex as any of the main games. Episodes I-IV and VIII only exists in the imagination of series' creator Yasumi Matsuno.
 * Square-Enix now owns the rights to the series after purchasing the original developing team, Quest, although Matsuno has been working for Square before that on the "Ivalice Alliance" series, which consists of the entire Final Fantasy Tactics series, Vagrant Story, and Final Fantasy XII (which is also part of the "main" Final Fantasy series as well).
 * Fur Fighters (subtitled Viggo's Revenge at least in the Play Station 2 version) starts with all the major characters' retired after already defeating Viggo the first time. Throughout the game there are hints to their exploits but there never was another game, and sadly probably never will be.
 * Averted with Metal Gear Solid 2 Sons of Liberty, which had the Working Title of "Metal Gear Solid III". The skip in numbering was hinted to be an important plot point.
 * Data Design Interactive's Rig Racer 2: There was never a Rig Racer 1, although the name echoes an equally horrible rig "racing" game.
 * Power Punch II. It was originally going to be a direct sequel to Punch Out titled Mike Tyson's Intergalactic Power Punch, but it was so bad that Nintendo refused to publish it, and Beam Software had to change the title and give it to a different publisher.
 * The story of Shenmue was planned out in roughly 16 chapters. The original game was just Chapter 1 (Yokozuka), while Shenmue II consists of Chapters 3 through 5 (Hong Kong, Kowloon and Guilin). Chapter 2 occurs off-screen between the events of the two games, while the remaining chapters were planned for future games that were never released due to the poor sales of the first two games.

Web Comics

 * Xkcd skips directly from #403 to #405. Attempts to view the URL where #404 would be if it existed result in HTTP error message 404 ("Page not found").
 * A strip did appear on the xkcd site between 403 and 405—but not an xkcd strip. 403 was posted on March 31, 2008, and 405 was posted on April 2. On April 1, the site displayed a (science-themed) Questionable Content strip, as part of a three-way switcheroo also involving Dinosaur Comics (which displayed an xkcd strip).

Web Original

 * The "Dinosaur" series of shorts by Waverly Films has no part three, but does helpfully recap the events of three at the beginning of part four.
 * Arfenhouse Teh Movie 3 and 4 were both released as April Fools' Day pranks in 2005 and 2006 respectively. Finally, a proper sequel, Arfenhouse Teh Movie 6, was released later in 2006, with no 5th installment.
 * Sad Panda Q&A skips episode 8. Apparently, it had cameos by a number of That Guy With The Glasses contributors, as well as The Angry Video Game Nerd and Yahtzee. Episode 9 starts with Panda and Welshy unsure on how to follow it.
 * One of the Homestar Runner Halloween specials has the title, "Jibblies 2," despite the fact the creators never released a toon titled, "Jibblies". Strong Sad lampshaded this in an Easter Egg.

Western Animation

 * American Dad: "Merlot Down Dirty Shame" begins with a recap of Stan and Roger bonding while trapped in an elevator. It ends with a preview of the next episode with.
 * Clerks the Animated Series: The first episode begins with Randall announcing "Last week on Clerks..." and cuts to a test pattern..
 * The Venture Brothers: "Escape to the House of Mummies, Part Two" begins with a "Previously On..." that shows the best parts of Part One and ends with a "On the Next..." for Part Three; neither actually exists.
 * The South Park episode "Awesom-o" mentioned a lost Lemmywinks sequel that never actually existed, the disclaimer claims it was lost because of the "disaster in Hawaii".
 * The Season 10 premire, "The Return of Chef", opens with a "Previously On..." depicting Chef leaving South Park to join the Super Adventure Club and his friends being upset over him doing this.
 * There was also the two episodes "Go God, Go", which ended with Cartman recently arriving in the far future, and "Go God, Go XII" which began with a Buck Rogers opening parody leading to Cartman seemingly months later, as if there were ten episodes about Cartman in the future that were just skipped.
 * Thomas the Tank Engine: The adaptation of "The Missing Coach" was scrapped during production because its plot was deemed too much of a Mind Screw for young children. The events are referenced in a later episode, so they did happen, we just never saw them.

Real Life

 * An accidental example exists in papal history: Owing to various misconceptions and transcription errors, there has never been a Pope John XX. The Pope who would have born that number skipped straight to John XXI when choosing his papal name.
 * Microsoft's Office 2007 is internally known as version 12. Office 2010 is known as version 14. Microsoft skipped the number 13 due to the superstitions related to it.
 * Chrysler's 300 "letter series" ran from 1955-1965. But the list of models skips from 300-H to 300-J. This is because the letter "I" too closely resembles the number "1".
 * There wasn't a year numbered 0, since the zero hadn't been invented yet. Only 1 B.C. and 1 A.D.
 * Even if the number 0 had been in use in the Roman Empire, using it in this context actually makes little sense. Saying "0 B.C." literally means "zero years before the birth of Christ" -- i.e., the year of Christ's birth, or 1 A.D. Likewise, since 1 A.D. literally means "the first year of Our Lord," saying "0 A.D." means "the zeroth year of Our Lord" -- i.e., the year before Christ's birth, or 1 B.C.
 * Not to mention the fact that when Christ was born (which may or may not have been 1 A.D.) very few people thought it was particularly important.
 * Many tall buildings were known to have Missing Floors. Examples include Las Vegas hotels which skipped the 13th floor entirely; and many government and supposedly privately owned buildings which allegedly had unnumbered floors with no elevator access. (Yet people who rode the elevators every day suspected something was up when it took twice as long to go from, say, the 18th floor to the 19th than it did to go from the 17th to the 18th.)

Examples where the unmade installment was later made

 * Star Wars episodes I-III were made and released many years after episodes IV-VI.
 * Spy Boy originally had no issue 13. After the original run ended, a three-issue miniseries named Spyboy: The MANGA Affair was given the numbering #13.1, #13.2, #13.3.
 * Homestar Runner was originally missing Strong Bad E-mail 22 in the original order, going straight from 21 to 23. Many episodes later, an e-mail was put into the slot, referred to as "The Lost E-mail", and explained that it had been "banned in the UK" for making fun of the English.
 * Strong Bad showed the viewers the gang's homemade action movie, Dangeresque 2: This Time It's Not Dangeresque 1, almost a year before showing them Dangeresque 1: Dangeresque, Too?
 * Nerd to the 3rd, a podcast for That Guy With The Glasses hosted by Dr. Gonzo, the Cat, and Travis, skipped over its 18th episode. Its 18th episode was later released as 'The Lost Episode', and it was an episode where they discussed the series finale of Lost with their guest Rollo T.
 * Starflyer 59 had a song called "Second Space Song" on their debut album. They wrote "Wherever You Go (First Space Song)" for the followup album, but it got cut and was only released on their Greatest Hits Album.
 * Bonus Stage episode 4 was originally a preview of projects the creator was working on, and didn't have an actual Bonus Stage cartoon, but between the season 5 finale "Fickle Nickel" and the season 6 premiere "Last Exit To Charismaville" it was replaced with a cartoon making several references to things happening after the original episode 4.