History WhatHappenedToTheMouse / Literature

** In his short story "The Jaunt", the protagonist's daughter almost literally asks this question when the protagonist tells the family the story of the eponymous teleportation device's invention. To wit, the inventor ran down to the pet store and tested some white mice out on the machine. Slightly subverted when he euphemistically explains that they "didn't feel so good the first time" after being sent through awake. [[spoiler:And by now you've probably guessed why he was being euphemistic with his family about what happened to those mice.]]

* Marcie, a girl in the first OrigamiYoda book, is mentioned once and never again in the entire series.

* At one point in ''[[Literature/WatershipDown]]'', rabbits tell the story of "The Black Rabbit of Inlé". At the end of story, god Frith waits for the hero and his trusty companion with the bag of gifts. The hero gets replacement ears, nose and tail. The reader never finds out what hero's trusty companion got.

** After the power of the primevals is broken in the ''Literature/InvasionCycle'', Treva, Dromar and Crosis are never seen again. They are commonly assumed to have perished during the invasion, but this has never been confirmed.

* It happens a number of times in ''TabeletopGame/MagicTheGathering'' tie-in novels. Due to the novel line being written by many different authors, characters can vanish between books, but sometimes it even happens within a single novel:

** After the power of the primevals is broken in the ''Literature/InvasionCycle'', Treva, Dromar and Rith are never seen again. They are commonly assumed to have perished during the invasion, but this has never been confirmed.

* In ''Literature/{{Julian}}'', a secret agent happens to see an imperial robe in a dyeshop. The [[TheCaligula increasingly insane]] Gallus has an innocent man executed for it, but it's never explained who the actual buyer was, and why.

* In ''Literature/{{Julian}}'', a secret agent happens to see an imperial robe in a dyeshop. The [[TheCaligula increasingly insane]] Gallus has an innocent man executed for it, but it's never explained who wanted it and why.

* In ''Malpractice in Maggody'', every member of the rehab clinic's staff eventually deserts the place or is called away except for Dr. Stonebridge, who's passed out drunk in his apartment. While the Mexican security guards are revealed to have departed with the orderlies and cleaning ladies, it's never stated whether they brought the German shepherd dog with them or left it behind in its kennel. If the latter, did anyone ever remember to let it out?

** Shann is able to tell that something is wrong at the post because a man working there is not in his garden. We do not learn whether he was prisoner, killed, or escaped.

* In Creator/AstridLindgren's book ''Literature/MioMySon'', the evil of Sir Kato is so pernicious, such a blight on body, mind and spirit, that the mere mention of his name causes the sky to darken and men and animals to weep. The little prince sees a number of butterflies lose their wings. [[spoiler: When Kato is defeated, the land, animals and people are all healed and one of Kato's servants who died to help the children even comes back to life. We can ''assume'' that the butterflies were healed too, but the author doesn't mention it.]]
* Joe Abercrombie's ''TheFirstLaw'' universe has an excellent backstory centering on the sons of Euz and how they created the modern world. The issue is that, of Euz' four sons, Juvens (the first), Kanedias (the second), and Glustrod (the fourth) all have the important moments of their lives and deaths detailed. The third son, Bedesh, is mentioned only once, and his eventual fate is not elaborated on.

* Literature/{{Dragonlance}}:
** Specifically the end of ''Autumn Twilight''. It's revealed early on that hoopaks are a kender's birthright (implying they inherit them from their parents) and Tasslehoff's fighting style incorporates the hoopak heavily. He uses it booth as a weapon and a distraction. Then, in the Tomb of Kith-Kanan, he says he loses it and leaves it behind in the tomb, and vows to return to get it. The sequel, Winter Night, takes place a few months later, yet for the rest of the trilogy (and the following trilogies) the hoopak is never mentioned again.
** The sword of Kith-Kanan itself. Tanis comes by the sword in a very fantastic way (apparently the skeleton of Kith-Kanan "gave" it to him), yet the sword doesn't do anything extraordinary in Autumn Twilight, and then when the fellowship is broken in Winter Night Laurana makes a choice to leave the sword behind with the elves so she can carry the dragon orb/ dragon lance. About sixty years later, in Lost Star, Laurana raids the Qualinesti treasury and pulls out another CoolSword, Lost Star. What happened to the Sword of Kith-Kanan?
* In ''Literature/LesMiserables'' and its adaptations, whatever happened to Valjean's sister and her kids that he stole bread for in the first place? Granted, 20 years have passed and he's now on the run, but one could imagine he'd find some way to check up on them if he could. They are given some mention later on -- Valjean gets some news that reveals that all but the youngest kid are gone, the sister works constantly to support them, the little boy trudges to school every day and waits for it to open, and in winter a kind lady who lives near the school lets him come in and sit next to the stove to warm up until it opens. Beyond that, they don't come up, and Hugo says he will not mention them and doesn't know what happened to the rest of the children.
** Some avoid this by having Valjean steal the bread for himself instead.
* In ''Literature/SingYouHome'', Zoe and Vanessa are fighting in court against Zoe's ex-husband Max in order to acquire the frozen embryos that Zoe and Max made in IVF treatments during their marriage. Max, who becomes a born-again Christian, plans to give the embryos to his brother and sister-in-law (who he also happens to be in love with), who are infertile. In the last chapter, Max starts contemplating just letting Zoe and Vanessa have the embryos, since he doesn't want to see his brother and wife happy together, knowing he can never be with his sister in law Liddy. In the epilogue, it is revealed that Max did give the embryos to Zoe and Vanessa, and is about to marry Liddy. This still leaves many questions unanswered. When did Max get together with Liddy? How did the court decide to give Zoe and Vanessa the embryos? Is Max still a Christian?
* In Creator/AndreNorton's ''[[Literature/{{Warlock}} Ordeal in Otherwhere]]'',

* In ''Literature/TheLionTheWitchAndTheWardrobe'', the animals having a dinner party before being turned to stone by the Witch (leading to Edmund's HeelFaceTurn) are never mentioned again. Aslan being omniscient and all, or perhaps Edmund told him, he probably gave them a visit to restore them, but who knows?
** Lewis got a What Happened to the Mouse? letter from one of his readers (or the reader's mom) and hastily wrote back a WordOfGod that ''of course'' the animals at the dinner party got turned back, just not on stage, and he was very sorry the child was distressed about the issue.

* W.E.B. Griffin's The Corps series has many viewpoint characters simply vanish from the narrative, especially when the series timeskips into Korea. While a couple are at least given some resolution, many simply vanish between books.

* In ''Literature/TheShortSecondLifeOfBreeTanner'', Freaky Fred runs away before the newborn army is sent to fight the Cullens. He is never mentioned again in the series, even though the novella ends with Bree mentally begging Edward to be kind to Fred if they ever meet.
** This happens pretty bad in regards to that novella. We see that for a pretty good stretch of time, there have been numerous abductions, disappearances, violent murders, suspicious fires and explosions, several residents being killed for their houses, a mall getting broken into and robbed, and an ''entire ferry of people getting murdered and sunk''. One would think that this would get national attention under suspicion of a terrorist attack, but in ''Breaking Dawn'', everyone has apparently forgotten about the insane amount of death and destruction that happened in Seattle. Of course, given that the story is told from the point of view of [[ItsAllAboutMe Bella]], that might explain the absence of such details...
* In-universe in ''Literature/TheFaultInOurStars'' by John Green. The main characters love a CutShort novel and want to know what happened to, amongst other things, the pet hamster.

* There's a fair number of these in ''Literature/{{Animorphs}}''. Joe Bob Fenestre from ''The Warning'', Derek from ''The Extreme'', & Mertil and Gafinilian from ''The Other'' are all one-shot characters who are set up to be bigger players but then never appear again. There's also the unexplained fates of recurring characters, namely StarterVillain Chapman and Loren ([[spoiler:who is Tobias's ''mother'' for crying out loud]]).

** We never hear very much about Cassie and Jake's parents and the being that caused Jake to see the alternate future in book ''The Familiar''.

** An odd [[SubvertedTrope subversion]]. While never the answer is never given in either of the books - as Dodgson meant for the riddle to be a riddle without an answer - enough of his fans pestered him about the riddle that he made up an answer: [[spoiler: "Because it can produce a few notes, though they are very flat, and it is 'nevar' put with the wrong end in front"]]. There is also the story a copyeditor 'corrected' the word [[spoiler: 'nevar' to 'never']] and the joke was lost.

* In the first ''Literature/MaximumRide'' book, the main characters (who are winged humans, part bird, part human, created by some MadScientists) have gone years without seeing another genetic experiment like them. When they get to a secret facility in New York, they find several experiments caged up. Naturally, they set them free. You'd think they'd want to talk to them or interact with them, maybe help them find a safe place, but it never goes anywhere. Over 5 books later, said experiments don't even get a passing mention, they're never thought of again, so it's a plot thread that went nowhere and contributed nothing to the story.
** ''Literature/MaximumRide'' suffers from this a ''lot''. The second book also has the group finding two kids in the woods. While Angel reads their minds enough to know that they aren't experiments, she can tell that they aren't normal kids. The kids use a tracking device to lead people from Itex to the group, and the most that's found out is that they were kidnapped solely for that purpose, and that they would be left to be eaten by something if they failed. The group leaves them in the woods to be recaptured by the company, and they're never thought of again. The third book has an entire facility full of successful experiments, including clones of Max (introduced in the book prior and herself having fallen into this trope until that point), Nudge, and Angel. It's never revealed what happened to the experiments after the facility is captured, and again the group never thinks anything of it. Meanwhile, Fang starts a worldwide revolution via the children that read his blog. You'd think that something like that would get a mention in the next book, but it might as well have not happened for all the aftermath there was.
* In ''The Nightmare Factory'', Dan is scarred by a creature called a Septaurus and slowly begins to transform into one (basically a family-friendly version of FaceFullOfAlienWingWong ). Oran gives him a potion that suppresses this transformation, even though it tasks terrible. In the sequel, ''Rise of the Shadowmares'', there is no mention of this transformation whatsoever. There isn't even any mention of the potion, despite the fact that some of the time intervals Dan has to spend between drinking it would [[Main/MagicAIsMagicA canonically be long enough for him to start transforming again.]]

* In book four of the ''Literature/InheritanceCycle'' Eragon and Arya wind up captured by a group of evil priests. A young novitiate appears and agrees to help them escape. He fails and winds up unconcious, while the more competent Angela comes to the rescue. Eragon insists that they take their would-be rescuer's comatose body with them as they escape the cathedral, however after this the boy is promptly dropped off in an alley and never mentioned again.
** The blind Varden soldier who mysteriously turns able to see magic energy disappears after being put in under vigilance from Du Vrangr Gata and is never mentioned again, not even in the saga's GrandFinale.

* The riddle from ''Literature/AliceInWonderland'': "Why is a raven like a writing desk?" was left unsolved by Creator/LewisCarroll...
** An odd [[SubvertedTrope subversion]]. While never the answer is never given in either of the books - as Dodgson meant for the riddle to be a riddle without an answer - enough of his fans pestered him about the riddle that he made up an answer: [[spoiler: "Because it can produce a few notes, though they are very flat, and it is 'nevar' put with the wrong end in front". (Among other suggested answers, Sam Loyd's "Poe wrote on both" is probably the best-known.)]]
*** Another suggestion of Dodgson's was "Because there is a B in both."

* Early on in the Literature/VorkosiganSaga novel ''The Vor Game'', Miles is assigned to Kyril Island as the new Weather Officer. The officer he is replacing has been there so long that he has developed a "nose" for predicting the weather, especially the deadly wah-wahs, which is far more accurate than the available equipment. Miles is briefly terrified that everyone else will notice a sudden drop in the accuracy of reporting when he takes over, but soon has a major confrontation with the commanding officer and is transferred off the island. Presumably the poor patsy who replaces him will be no better at predicting the weather than Miles, but the island is mentioned just once more in a later novel, a decade later in book time, and it's implied that nothing has changed there.

** Cornelius Fudge, the Minister of Magic for most of the series. His last official position we hear of is at the start of book 6, where he's been sacked as Minister, but is kept on as liaison between the Ministry and the Muggle Prime Minister. No word at all of him or how he reacted to Voldemort taking over the Ministry in Book 7.
** It was never explained what was behind the veil [[spoiler:that Sirius fell through when dying in book 5,]] though as it is in the Department of Mysteries, it is likely that no-one knows.
*** Even though in the movie [[spoiler:Sirius was dying as he fell]], in the book it's obvious that [[spoiler:the fall through the arch is what killed him]]. So, it's fairly clear what lies behind the arch, especially when you take into account what Harry heard from it. Luna's comments to Harry at the end of the book would seem to confirm this theory, but then again, [[{{Cloudcuckoolander}} consider the source]].
** It is never revealed what happened to Lavender Brown at the end of the seventh book. She is seen attacked by Greyback, then Hermione saves her, she was seen "feebly stirring" and never mentioned again. We have no evidence she lived or died. The movie resolved this by making her die.
** Also Winky, who we last saw as an [[TheAlcoholic alcoholic wreck]]--which was probably not helped by finding out that [[spoiler:Barty Jr. killed Mr. Crouch]]. She's briefly mentioned afterwords but not in the final book, though WordOfGod says she (somehow) got over her problems and took part in the Battle of Hogwarts.

* One of the many things wrong with ''Literature/TheLegendOfRahAndTheMuggles'' by Nancy Stouffer is the sheer number of mouse plots in the story. The mother of the twin protagonists, having been recently widowed at the start of the story, enters a very heavy flirtation with the palace butler before shipping her kids off to save them from impending doom; what becomes of the mom and the butler, we never know. Later, the twins are deeply involved in the search for a specific treasure chest; when it's found, the bad twin insists on claiming it, to which the good twin consents. Not only is it never mentioned again, but the reader never even finds out what was ''in'' the chest that was so important.

* At the end of ''{{Literature/Frankenstein}}'', the doctor mopes that everyone he loves is now dead. However, we never hear what happened to his brother Ernest.

* In the ''Literature/SwordOfTruth'' series, Richard's two hulking bodyguards Ulic and Egan disappear from the narrative entirely after ''Temple of the Winds'', and no reference is made to where they are, or what they're doing. Their sudden and conspicuous return to the plot in ''Confessor'' seems to suggest Goodkind actually forgot about them entirely.