An episode in a series that serves as a sequel to a previous episode. Different from a Multi-Part Episode, in that there may be several episodes (if not several years) between the first episode and the one that picks up the plot again.
To qualify, it's not enough to simply have an object, setting, or character from one episode appear in another, otherwise any series with a Rogues Gallery would consist almost entirely of Sequel Episode. If Cop Show has the Main Characters arrest a thief and recover some stolen jewels in one episode, and a later episode has the thief break out of prison and cause some more havoc, that's just a One-Shot Character moving up to Recurring Character status. If, on the other hand, a later episode has the cops discover that the stolen jewels they recovered were actually fakes, and they have to interrogate the thief to find out where she hid the real jewels, that is a Sequel Episode; the plot resolved in an earlier episode is reopened and explored again in a new episode.
Obviously this only applies to series where standalone episodes occur somewhat regularly. If the whole show is one long Story Arc, there's not enough separating the plot of one episode from another to make labelling it a "sequel" meaningful. However, if a series has multiple story arcs, it is possible for a later Story Arc to be a sequel to an earlier one. A show with half arc seasons can also have these based on the stand-alones.note Compare Myth Arc, which can be seen as a series of these in an otherwise episodic show.
- Ghost in the Shell: Stand Alone Complex actually categorizes its first-season episodes as "Stand Alone" episodes and "Complex" episodes, of which the former are Exactly What It Says on the Tin, and the latter are a handful of Sequel Episodes around one major Story Arc.
- In Kirby: Right Back at Ya!, various episodes get this treatment, but special notability goes to "The School Scam" and "Teacher's Threat" (sequels to "eNeMeE Elementary"), which are actually titled "Demon Teacher 2" and "Demon Teacher 3" in Japan.
- In the middle of the Johto Arc of the Pokémon Anime, the episode where Brock meets up with Suzie and her friend Zhane at a breeders' competition counts as it recalls a few points about breeding mentioned in Suzie's original appearance in Kanto and has Brock give back the Vulpix he got from her in said Kanto episode.
- One of the most popular Iron Man stories was Armor Wars in the 80s. Subsequently there have been two sequels to the arc, Armor Wars II (in the 90s) and Armor Wars III (in 2012).
- Roger Stern's Spider-Man story, "Nothing Can Stop the Juggernaut" from the early 80s, in which Spidey fights the recurring X-Men villain Juggernaut, was followed up by 2009's "Something Can Stop the Juggernaut". And to make it even better, the sequel was written by Stern as well!
- Don Rosa wrote several stories in the Disney Ducks Comic Universe that serve as sequels to stories by Carl Barks (Rosa was a big fan of Carl's works growing up). "The Money Pit" is a sequel to "The Trouble With Dimes", "Return to Plain Awful" is a sequel to "Lost in the Andes", and so on.
- Noob: In Comic 5, Sparadrap turns out be a Genius Ditz at fluxball, the Fictional Sport that has been added to the setting of the fictional MMORPG everyone is playing. This results in the titular guild winning a tournament of the sport that has been organized to promote the new activity. Starting Comic 6, the story turns into its own retelling of the franchise's Myth Arc, in which fluxball plays absolutely no role. In Comic 12, which happens during a time period other media of the franchise skipped over, the Noob guild goes to Japan to participate in an international fluxball tournament due to technically being the top team in France after the events of Comic 5.
- FoxTrot did a months-long story where Jason and Marcus goes to a summer camp, with Eileen and her new friend Phoebe. Several years later, they did a follow-up where Phoebe visits their city.
- One Retail story ended with Cooper getting Keith Sanzen arrested. Years later, Keith returned as an inventory supervisor, still bitter over his arrest.
- The Calvin and Hobbes storyline with the duplicator had a sequel where Calvin perfected the device (he added a literal Morality Dial).
- The Redwall series currently consists of several vaguely related stories that take place in the same universe. However, there are a few cases of Direct Sequels. Mattimeo was sequel to the Original book; Mossflower has a sequel in Legend of Luke and a prequel in Martin the Warrior, and The Bellmaker is a direct sequel to Mariel of Redwall.
- Spock's World reopens the events of "Amok Time" as the motive for the Big Bad.
- Inverted in Agatha Christie's novels Murder on the Orient Express (published 1934), Murder in Mesopotamia (published 1936) and Death on the Nile (published 1937), all of which take place on the holiday that Poirot takes in the Near East. The inversion is due to the fact that the stories are prequels to each other, for in Poirot's chronology, he goes down the Nile, visits Mesopotamia, and then travels on the Orient Express, the events occurring in reverse publishing order.
- Frequently happens with Black Library stories, where authors often revisit plot threads from earlier books, often with many years and various different books passing between. This tends to happen a lot between Horus Heresy and "present day" stories, such as Titanicus, which continues the story of the stolen book from Mechanicum, though taken place thousands of years later (while also being a spinoff of the Gaunt's Ghosts series that explains why the Titan legion that was supposed to back the eponymous team up in one of the earlier books couldn't make it).
- Anthony Price's 18th spy novel, A Prospect of Vengeance, is a sequel to his 9th, Tomorrow's Ghost. A team of investigative journalists come across the loose ends of the earlier novel, and the reader gets a chance to find out what happened after its abrupt ending.
- Iron Maiden had the tale of Charlotte the Harlot chronicled in 4 songs from 1980 to 1992: "Charlotte the Harlot" (Iron Maiden, 1980), "22 Acacia Avenue" (The Number of the Beast, 1982), "Hooks in You" (No Prayer For the Dying, 1990), and "From here to Eternity" (Fear of the Dark, 1992).
- Metallica with "The Unforgiven" on their self-titled album in 1991, and then "The Unforgiven II" on the album Reload in 1997, and finally "The Unforgiven III" on the album Death Magnetic in 2008.
- Megadeth had the fan favorite song "Hangar 18" on their 1990 album, Rust in Peace. In 2001, they released a sequel song, "Return to Hanger" on the album The World Needs a Hero.
- Manowar had a unique case of prequel episode (song), with "Metal Warriors (Brothers of Metal Pt. 2)" released in 1992 on their Triumph of Steel album, and the "Brothers of Metal Pt. 1" released in 1996 on their Louder Than Hell album.
- Overkill have: "Overkill", "Overkill II (The Nightmare Continues)", "Overkill III (Under The Influence)", "Overkill IV (E.Vil N.ever D.ies)" and "Overkill V (The Brand)". Confusingly, they covered the Motörhead song "Overkill" as well (the source of the band's name, and a completely different song).
- Queensrÿche broke through with their 1988 Concept Album, Opertaion: Mindcrime. They made a sequel album in 2006, Operation: Mindcrime II and performed both albums back-to-back while on tour that year, chronicled on the DVD, Mindcrime At The Moore.
- He Is Legend's first album included the track "The Seduction" which was followed by "Dixie Wolf (the Seduction of...)" in their second album. They also had one of "China White" parts 1, 2, and 3 in each of their three albums.
- Sluggy Freelance gave us the horror movie spoof "KITTEN", and naturally it couldn't parody horror movies without parodying the inevitable sequels; hence, "KITTEN II".
- Dragon City does this from time to time with story arcs. There was at least one story arc that have about four or five story arcs that were sequels of it and of each other since the latter ones were consequences of the first story arc.
- Jix, which is by the same person who created Dragon City, also does this from time to time, but possibly not as extensively as Dragon City.
- The "Sister II" arc of El Goonish Shive is rather predictably a sequel to the much earlier "Sister" arc. The initial "Sister" arc dealt with the events surrounding Ellen's creation via the Dewitchery Diamond, and the start of her journey to become her own person separate from Elliot who's memories she shared. The sequel primarily dealt with the fallout, such as the wizard who made the diamond, and swore to destroy any "abominations" created by it, and the fact that touching the diamond in the first place had a slightly greater effect on both Elliot and Ellen than anyone realized at the time.
- 20 Ways to Lose Your Man Card by Matt Santoro details a symbolic representation of one's manliness. It recieved a followup called 20 MORE Ways to Lose Your Man Card.
- SiIvaGunner's high quality "Main Theme - Ubisoft E3 Conference 2016" rip is mostly him ranting about the lack of Beyond Good and Evil 2 in Ubisoft's E3 conference that year. The following year, his "Main Theme - Ubisoft E3 Conference 2017" rip has him travel to 2017 (when Max Profitt Haltmann has taken over his channel while he's asleep) to discover that Ubisoft is indeed making the game.
- Star Trek Continues, itself a Fan Sequel to Star Trek: The Original Series, was found of doing this with several episodes:
- "Pilgrim of Eternity" is a sequel to "Who Mourns for Adonais?", and even features Apollo's original actor, Michael Forest, doing a Role Reprisal.
- "Fairest of Them All" is a sequel to "Mirror, Mirror", though with the twist that it is seen from the perspective of the denizens of the Mirror Universe.
- "Still Treads the Shadow" is a very, very dark sequel to "The Tholian Web".
- The two part finale, "To Boldly Go", works as a sequel to "Where No Man Has Gone Before", though more in the sense that it is meant to form Book-Ends with that episode.