This is the uncanny habit of a new character arriving conveniently in time to replace an outgoing one, generally in the same episode. Sometimes there is a certain logic to this, as in the case of Starfleet officers being succeeded by another of the same rank. Other times, it's just to make up the numbers, such as in Blake's 7, when the new character is always the same gender as the outgoing one.
A frequent vehicle-of-delivery for the Suspiciously Similar Substitute.
- In One Piece, immediately after Vivi decides to stay behind to help rebuild Alabasta, Robin joins the crew, replacing Vivi as the other female Straw Hat.
- This is what Luffy and Chopper think happens during the Enies Lobby arc. In reality, "Sniper King" is a paper thin disguise of Usopp's that he adopts in order to help save Robin without admitting that he's helping the Straw Hats, whom he had just dramatically left. Robin, Sanji, Nami, and Zoro all see through this, but choose to keep the secret.
- Pokémon: The Series:
- With each new region Ash travels to in (besides Johto), Ash is accompanied by a different female companion. Misty from the original series is succeeded by May in Pokémon the Series: Ruby and Sapphire, then Dawn in Diamond and Pearl, then Iris in Black and White, then Serena in XY. Note that each character from May on (except for Iris) is the female player character from her respective video games (whereas Ash starts wearing the outfits inspired by the male player character beginning with Diamond and Pearl). Starting with Black and White, Ash's male companion is also different and largely serves in the same roles (being a Gym Leader, The Lancer and a Team Chef). This trend largely ended with Sun and Moon due to retooling the general plot from traveling around the region with constant companions to Ash attending a school with his classmates not appearing in every episode. Pokémon Journeys: The Series has him traveling again (albeit through several previous regions in addition to Galar) with a new companion, Goh, but he's a male character not based on any playable character or Gym Leader from the games, and isn't intended to be a replacement for any single character from the Sun and Moon saga.
- Before cast changes between regions became standard, Brock was then-temporarily Put on a Bus just one episode after the group's visit to the Orange Islands started. In the very next episode after that, Tracey is introduced and conveniently joins the group in Brock's place. This trope is then inverted in the episode right after Ash and co. return from the Orange Islands, where Brock rejoins the group and shortly afterwards, Tracey decides to stay behind.
- This also happens with a few of Team Rocket's Pokémon. Cacnea joins up with James in the very same episode he and Jessie bid a heartbreaking farewell to Weezing and Arbok. Two episodes later and Jessie has a brand new Seviper in place of her Arbok. Later on, James befriends and catches a Mime Jr. in the same episode he is forced to part ways with his Chimecho.
- In Tengen Toppa Gurren Lagann, Nia shows up one episode after Kamina is Killed Off for Real. In some ways she serves as a Foil for him, providing calm encouragement in contrast to...well…
- In Dr. Blink: Superhero Shrink, Jimmy Hogan was interviewing with Nocturne for the position of Kid Sidekick when Wonder Boy IV accidentally ate a booby-trapped Mostess Fruit Pie.
Nocturne: So... uh... can you fit into size three spandex?
- Wonder Woman Vol 1: Steve Trevor seems to go through secretaries rather quick, since his have a habit of being compromised (and thus fired), turning out to have been spies, or getting murdered. He always seems to have a new one by the next day.
- In the Supernatural/Wynonna Earp crossover series Told That Devil to Take You Back, Sam Winchester- believing that Dean is dead after the confrontation with Amara- basically takes the role that Marshal Xavier Dolls had in canon, using his fake badge to pose as a U.S. Marshall and telling the sheriff that Wynonna is his deputy.
- Essentially applies to Rohvu's Pilot from Crichton and Chiana's perspective in Left Behind; he's less confident than Moya's Pilot, but he's still similar enough that it's easy for them to accept this Pilot as a friend.
- The Gamers: Parodied when one player's tabletop game character is killed. A physically and mechanically identical replacement appears from Behind the Black in the next scene, despite the remote location.
Game Master: Remember, you've never met this guy before, the last guys you met tried to kill you, and you're standing in the ruins of an evil, cursed castle. Just... act appropriately.
Magellan: Hello! I'm Magellan, a traveling mage. I notice your group has no wizard.
Rogar: You seem trustworthy! Would you care to join us in our noble quest?
- In the Warrior Cats book Sunrise, one of the protagonists dies toward the end of the book (or at least appears to). Right afterward, the book ends with two new kits being born, and one of them ends up replacing them as the third protagonist in the next book.
- In the sci-fi novel Wyrm, the main characters are very much deep into the viral MUD central to the plot when one of the characters they're playing dies. Luckily, that player just happened to have a back-up character that had been following close behind them the whole time without them noticing.
- Doyle makes a Heroic Sacrifice to save the title character of Angel. Wesley arrives in town in the next episode.
- In Blake's 7 Jenna is replaced by Dayna, Blake is replaced by Tarrant, and Cally is replaced by Soolin.
- In Bonanza, Will Cartwright was set up to be this for Adam Cartwright, but it was subverted when Will ended up leaving the show before Adam did.
- In Bones, Sweets' friend James Aubrey is introduced in the first episode of Season 10, just before Sweets dies in the very same episode.
- Charmed is based around the concept that three specific witch sisters are The Chosen Ones because they have a special bond called "the Power of Three." So what to do when one of those sisters is killed off after her actress left the show? Reveal that there was a fourth sister whom they didn't know about! To be fair, it worked surprisingly well — their mom's affair with her Whitelighter was already established and provided a logical reason for Paige to be given up for adoption. She shows up right after Prue's death because of a spell that Piper cast to reestablish the Power of Three, which had been intended to bring Prue back.
- CSI: NY: When Melina Kanakaredes decided not to return after 6 seasons, Det. Stella Bonasera is revealed in the season 7 premiere to have transferred to New Orleans to head up the crime lab there, and Det. Jo Danville arrives just after the Cold Open to fill her position.
- Doctor Who traditionally did this with great frequency, although there was an aversion in the last few Tenth Doctor stories. Possibly justified on the grounds that the Doctor gets lonely without a companion, or foresees one leaving, and starts actively looking for a new one. Especially during Steven Moffat's term as showrunner, there are references to no-companion adventures... which are conveniently off-screen.
- The Dukes of Hazzard: Bo and Duke leave to race cars, enter Suspiciously Similar Substitutes Coy and Vance. Bo and Luke return after the actors' contract dispute is settled, Coy and Vance leave town to aid a conveniently ill relative.
- When the actor who played Coach on Cheers died, they brought in Woody, not only to fill the job of tending bar, but also the job of The Ditz.
- Zigzagged on Farscape. Jool first appears in the same story where Zhaan leaves and takes over the position of ship's medical expert. However, Stark, who replaces Zhaan as the ship's mystic, had been an on-and-off guest star for a season prior to Zhaan's departure. Sikozu shows up to replace Jool as the annoyingly smart redhead chick a few episodes before Jool actually leaves. Averted with Noranti replacing Stark: there's a fairly large gap between Stark's departure and Noranti's introduction.
- In Frontline, each season features a new executive producer, all of whom are equally amoral but manipulate people in slightly different ways.
- Last of the Summer Wine: It almost always happens when one of the members leaves the trio. Seymour is called out of retirement and leaves, and the long-gone Foggy returns to the village on the very next bus. Years later, Foggy is supposed to be temporarily out of town, and the lads hang out with Truly Truelove in his absence. However, Foggy's trip becomes permanent when he suddenly marries, and Truly simply carries on in his place.
- Law & Order: Special Victims Unit: In the first episode of the second season, Ice-T's character shows up, having been reassigned to SVU. Monique Jeffries, Michelle Hurd's outgoing character, comments, "You're here for my job."
- Legends of Tomorrow: Happens fairly often due to the Revolving Door Casting. For example, in season 2, Vixen and Steel join the team to replace Hawkgirl and Captain Hunter. During season 3, when Jax leaves after Martin dies, Wally joins shortly after.
- M*A*S*H: The In-Universe reason is that units have certain roles that need to be filled, so when the show eliminated a long-term role, someone else needed to take that position.
- When Capt "Trapper" left, the army sent another surgeon to the 4077th. BJ happened to get along just as well with Hawkeye and the two formed a similar friendship as civilian doctors forced into military service.
- Commander (Lt Col) Henry Blake was sent stateside and his replacement, Col Sherman Potter, appeared soon after. The two characters are very dissimilar as Blake was as Mildly Military as the drafted doctors, while Potter was a career army surgeon who used to be part of the cavalry. Although their military roles were the same, the two provided very different contexts for the show's drama.
- When Cpl O'Reilly (known as Radar) goes back to America, Cpl Klinger is assigned to the same role: company clerk. While Radar made the job seem really easy and kept the camp functioning despite the absent leadership of Blake, Klinger takes over during Potter's tenure and starts off making a mess of things since he doesn't know the job very well. He grows into the role and functions at least as well as Radar in the role.
- Maj Frank Burns is the highest-ranking surgeon, next to the Commanding Officer. In a normal unit, he would've been the Executive Officer and is often shown as the second-in-command. When the character went crazy, he was promoted and replaced by Maj Charles Emerson Winchester III. Although they were the same rank and both were (effectively) XO, Winchester was a much better surgeon than Burns, and would remind everyone that he was the best surgeon in Korea.
- In Minder, Arthur's nephew Ray arrives looking for a job in the same episode (the season opener) that Arthur learns Terry has emigrated to Australia.
- The Joel-to-Mike swap on Mystery Science Theater 3000 was a justified example: Mike's first episode is Joel's last because Mike helps Joel to escape. Upon discovering that Joel is gone and they need another test subject to continue their experiments, the Mads force Mike to take Joel's place.
- NCIS: After Agent Caitlin Todd is murdered in the season 2 finale, Ziva David appears in the two-part opening episode of season 3 - which still features Kate, after a fashion (she is appearing as other character's hallucinations of her) - but isn't revealled to be a regular until an episode or two later. Actually subverted when Ziva leaves: She leaves the cast in the second episode of Season 11, but her replacement, Ellie Bishop, doesn't arrive until mid-November.
- NewsRadio: After dealing with Bill's death in the first episode of the fifth season, his replacement, Max Louis, is introduced in the next episode. Partially justified: it's a radio station and they do need an announcer (but not necessarily a wacky announcer).
- Out of This World (1987): Once Beano was gone, Evie suddenly had a new uncle, Mick, who had never been mentioned before.
- Rookie Blue: In Season 3, Sam's ex-bf, Detective Luke Callahan, returns to the division seemingly just in time for the current lead Detective Jerry Barber to get fatally stabbed within the next two episodes, leaving Luke to step up into Barber's old role.
- Averted by "The Best of Both Worlds", the Star Trek: The Next Generation season 3/4 two-parter. It looks like Shelby will be taking Riker's place as first officer, first when he's given his last shot at a command assignment, then when Riker assumes command of the Enterprise after Picard's abduction, she actually does become his first officer. Of course, Picard is saved, the ship Riker was offered command of is destroyed, and Shelby moves on to something outside the focus of the show.
- The reasoning behind this is worthy of mention, however. As, originally, Picard might have left for Season 4. Thus, it was written so that, in a pinch, they COULD have had the shake-up.
- In Star Trek: Voyager, Seven of Nine is introduced in the season 4 premiere (carrying on from the season 3 finale's cliffhanger). Kes leaves the show in episode 2 of Season 4 (after it's established that Seven is staying).
- Stargate SG-1: In the Daniel Jackson to Jonas Quinn swap, Jonas is introduced in "Meridian", which is the same episode Daniel gets sent off to a higher plane. And then, when Daniel comes back, that fits this too; Daniel's back, so Jonas skedaddles back home same episode.
- A few of the early Super Sentai and Power Rangers seasons had this happened whenever a retiring cast member needed to be replaced:
- The two replacements in Battle Fever J. Maria Nagisa shows up just when Diane Martin (Miss America) gets injured, whereas Makoto Jin happens to befriend Team Battle Fever just before Kensaku Shiraishi (Battle Cossack) is killed.
- Taiyou Sentai Sun Vulcan has The Hero Ryuusuke Oowashi (Vul Eagle)'s classmate, Takayuki Hiba, arrive after a hard battle. He's given a tour of the heroes' new base, and then their commander informs Oowashi that he has to go pilot a space shuttle for NASA. Of course, Hiba turns out to be there to replace him as the leader of the team.
- We also have the second Yellow 4 in Choudenshi Bioman, though plot allows the replacement to arrive smoothly: the Biomen are the descendants of people who'd been showered with Bio Particles during the Edo period. There are, of course, more descendants than just those five, and the Biomen went and recruited one.
- Done regularly on Mighty Morphin' Power Rangers, seeing as only one of the original Rangers (Billy) stayed through the entire multi-season first story. Rocky, Adam, and Aisha befriended the Rangers before replacing Jason, Zack, and Trini in Season Two; and then Kat showed up for an arc before replacing Kimberly in Season Three.
- Power Rangers Turbo worked similarly; Justin was introduced in the same movie where Rocky got sidelined, and midseason it introduced four new characters before they became the replacement Turbo Rangers.
- Power Rangers Lost Galaxy was a partial aversion, as when Kendrix had to be written out due to Real Life Writes the Plot, both planned replacement characters were returning from the previous season Power Rangers in Space. It's only "partial" because both conveniently made their reappearances just as Kendrix left: Cassie was part of the Lost Galaxy/in Space crossover that led to Kendrix's death, and when the plans for Cassie to be a permanent cast member fell through Karone appeared and became the new Pink Ranger in the following episode.
- Two and a Half Men: Walden Schmidt shows up the same episode we found out Charlie was killed.
- UltraMantis Black was injured and Blind Rage was retired, so Hallowicked didn't have a partner going into CHIKARA Tag World Grand Prix 2006. The names The Rockin' Rebel and Roderick Strong were both drawn, but they were not there. Delirious' name was drawn and he was there. They defeated Crossbones and Rorschach with a Doomsday Device in the first round on Night I and Cheech and Cloudy later that same night. They defeated Team DDT (KUDO and MIKAMI) in a Quarter-Final on Night III but lost to the eventual winners The Kings of Wrestling (Chris Hero and Claudio Castagnoli). They would go on to win the CHIKARA Campeonatos de Parejas in 2007.
- Boris Zhukov came into WWE from the American Wrestling Association as the new tag team partner for Nikolai Volkoff after The Iron Sheik was fired following his and "Hacksaw" Jim Duggan's drug bust in 1987.
- Warlord, a Dungeons & Dragons-inspired and highly self-aware Collectible Card Game, spoofed this with the card "Meet at the Inn"; its Flavor Text:
"Come on, guys! I have an overwhelming urge to go to the nearest inn and meet a pair of strangers who will help us in our quest!"
"What, so soon after our two friends died?"
- Near the end of the first dungeon of Baldur's Gate II: Shadows of Amn, Yoshimo offers to join your party. Imoen, your thief until then, is arrested by the Cowled Wizards at the end of the dungeon, so Yoshimo becomes your thief, at least until you can recruit Nalia or Jan. Yoshimo betrays you and dies once you enter Spellhold (where Imoen is imprisoned), and immediately afterward, you get Imoen back.
- In the second Digital Devil Saga, when you lose one of your party members partway through the game, Sera inherits their Demon transformation, and she joins the party with their exact stats, skills and mastered Mantras. However, Serph later rejoins the party and the two co-exist for a while. Then it's taken to its natural conclusion in the final dungeon, where the two end up fused into a single party member, Seraph, who inherits the highest of their individual stats and both their skills.
- Near the end of Dragon Age: Origins, sparing Loghain will lead to him replacing Alistair as your weapon-and-shield Warrior when Alistair storms off in a rage. In the Awakening expansion, Mhairi serves as your weapon-and-shield Warrior until she dies in the Joining, and Justice replaces her some time later.
- Eternal Eden ensures that you'll never have more than 4 people in your party by having someone leave or die before the next party member is introduced.
- Final Fantasy:
- Final Fantasy IV is practically the embodiment of this trope, as another party member will appear to fill in a gap left by a previous party member leaving, typically by Heroic Sacrifice. Unlike in many cases, the replacement character is often very different in terms of abilities and personality; after Palom and Porom(respectively a black mage and a white mage) turn themselves to stone to save the others from Cagnazzo's trap, they're replaced by Cid, who's more of a fighter.
- In Final Fantasy V, you add Krile to your party literally the moment Galuf dies. The new character even gets all the old character's skills and equipment, making it feel like all you've really done is a sprite change (though she is a significantly different character).
- Final Fantasy II. You have your core 3 characters, and the fourth one dies, leaves, gets separated, dies, or dies. You don't get your final party until towards three-quarters of the way through and that's your original party from the original cutscene. This is a nuisance seeing as the grinding system in this game depends on repeating one action repeatedly in order to become better with that action, so your fourth party members (with one exception) are all but useless.
- Fire Emblem:
- In Fire Emblem: The Blazing Blade, whenever Nils leaves your party, Ninian joins and vice-versa. Both serve the same role in gameplay and are in fact treated as the same unit for gameplay purposes; sharing their base stats, growth rates, and levels.
- In the remake of Fire Emblem: Shadow Dragon & the Blade of Light, if Tiki gets killed off, she'll be replaced by a Manakete named Nagi, who does similar things in the plot like gives you the (weaker form of) Sword of Plot Advancement. Speculation abounds just who or what she is, possibly a reincarnation of Tiki or Naga, but this is never answered.
- Fire Emblem: Three Houses:
- After the Time Skip on the Blue Lions route, Dedue will be executed, although he will later return if you did his Paralogue. In exchange, you get Gilbert, a character who plays a similar role (an armored knight, or "tank" who acts as their lord's second-in-command), just as the one who'd just left.
- A particular example can occur if Byleth leads the Black Eagle house but sides with the Church after the Holy Tomb incident. After Edelgard leaves the party, the player can get Hilda, who has a similar build and thus serve the same purpose as an unit. However, unlike most examples, Hilda needs to be recruited on a narrow time frame in order to count as such, and even then, the character will have no story relevance on the proper plot. On the other hand, in later updates on the condition of choosing Edelgard after the Holy Tomb battle and taking the Crimson Flower route the player automatically gets Jeritza/the Death Knight as a pre-promoted Lightning Bruiser unit, since Seteth or Catherine, who hold this position in other routes, won't be available on that route.
- The Legend of Dragoon gives us Albert after Lavitz is killed and Miranda after Shana loses the power of her dragoon spirit. Both join the party immediately after their predecessors can no longer travel with the party.
- In Lunar: Dragon Song, Lucia leaves your party a short way into the game. Unfortunately, she's the party healer. Fortunately, Flora joins your party shortly thereafter and brings her own healing with her.
- You are the replacement astronaut in Rama after the mission commander's mysterious death.
- Symphony Of War: Almost immediately after the player is released from prison without any of their old friends in tow, they meet Abigayle, a cleric who just so happens to be the sister of one of your previous party members and have a similarly optimistic personality.
- In Tales of Symphonia, shortly after Kratos leaves the party after being outed as a traitor and an angel in disguise, Zelos takes his place as The Red Mage of the group, having a very similar moveset and also wielding a sword and a shield. If Zelos dies, Kratos rejoins the party and becomes Zelos' replacement for the endgame.
- While old characters are killed off and new characters are introduced infrequently on Beast Wars, Scary Scorpion Quickstrike notably debuts the very episode after the Predacons' old scorpion-shifter Scorponok is destroyed.
- Freakazoid!: In "Mission: Freakazoid", Freakazoid's "mute butler" Ingmar leaves to pursue his dream of working in a rodeo, but fortunately Freakazoid is able to hire a new manservant in Professor Jones.
- Played for Laughs on Futurama, as we learn that the protagonists are actually this for Planet Express's last crew, who died horribly shortly before the series. One episode shows that Professor Farnsworth already has a Similar Squad picked out for his next crew, too.