History AdaptationExplanationExtrication / LiveActionFilms

** ''Film/XMenApocalypse'' doesn't waste any time explaining how [[ComicBook/{{Storm}} Ororo Munroe]] wound up living in Egypt, despite being (by all appearances) of sub-Saharan African descent. The ''ComicBook/XMen'' comics explain that she was born in Harlem to an African-American father and a Kenyan mother, but moved to Cairo as a child.

** The films' prologue briefly explains the story of the 19 rings that were forged alongside the One Ring (three for the Elves, seven for the Dwarves, nine for the Men); while we're told that the nine human ring-bearers became the ''Nazgûl'' (Ringwraiths) after being corrupted by their rings, audiences who haven't read the books are left to wonder what happened to the other ten. The books explain that the Dwarves' seven rings were lost after their kingdoms were consumed by dragons, while Gandalf, Elrond, and Galadriel ''still'' have the Elves' three rings.[[note]] Gandalf was given the ring ''Narya'' by the Elf lord Círdan, Elrond inherited the ring ''Vilya'' from the Elf lord Gil-galad after his death, and Galadriel has carried the ring ''Nenya'' since it was forged.[[/note]] Extra-attentive viewers might notice those three characters wearing rings that resemble the ones donned by the Elves in the prologue, but might wonder why they're able to freely wear them without being corrupted. The answer is that the Elves' three rings are a separate class of rings that were forged by the Elf smith Celebrimbor rather than by Sauron, and they're impervious to Sauron's magic.

** It's explained in the book that the White Witch's Turkish Delight is [[GRatedDrug instantly addictive]], making Edmund's betrayal over a supply of candy seem far less petty.

* Creator/DavidLynch's ''Film/Dune1984'' is one big mess of this. Hardly anything is given a proper explanation, and the film even features a few setups to plot threads whose payoffs are not included.

* The novel ''Literature/WhoCensoredRogerRabbit'' (which ''Film/WhoFramedRogerRabbit'' is based on) has a TwistEnding that explains the seemingly implausible pairing of Jessica and Roger: [[spoiler:the MacGuffin is actually a magic lamp containing a genie, which granted Roger two wishes--one of which was to marry Jessica]]. As the plot of the novel is completely different from the film, however, the movie's version of the Jessica/Roger relationship is simply treated as some strange, funny case of DeliberateValuesDissonance between humans and Toons (since humor is so prized in Toon society, ''she's'' considered the one who married up in the film).

* ''Film/MinorityReport'' completely did away with the ending of the short story due to its MindScrew nature. In the short story TheReveal is that there were ''three'' minority reports, the first pre-cog reported a future where Anderton committed a murder, the second a future where Anderton read the first report and refused to commit the murder, and the third a future where he read both the two earlier reports and committed the murder; three very different futures, and some of them contingent on predictions of the others. It is also mentioned that the only reason this could happen is that Anderton, as head of Pre-Crime, had access to the raw data from the pre-cogs rather than the cleaned-up version from the analysis computer. The film favors a far simpler turn of events that places less importance on how Pre-Crime actually works. There Anderton accidentally awakens a precog, who shows him a vision of her mother's murder - which was arranged by the BigBad. Anderton retrieves the vision and shows it to the BigBad - who then decides HeKnowsTooMuch, and hires a junkie to confess to the murder of Anderton's son, the one thing that would drive Anderton to murder.

** The first book ended with Nublar island being carpet-bombed by the (funnily non-existent) Costa Rican airforce, hence Ingen's new ruling bureau's (and in the second book, Biosyn's) need to go to the "Site B" and get their dinosaurs there. This was actually explained in a scene of the ''Lost World'' movie but was left out of the theatrical cut, leaving the casual viewer wondering why Ingen didn't just go back to Nublar, the island with some working infrastructure left and pick some of the dinosaurs still penned up there, rather than massing "two dozen cowboys" and going to catch the entirely free ones in Sorna.
*** This question was compounded when ''Film/JurassicWorld'' established that Isla Nublar did survive in the movie continuity, meaning that either the bombing did not take place in the movie canon, or the damage from it was less than one would expect.

* In ''Film/{{Cinderella 2015}}'', Gus Gus retains his name from [[WesternAnimation/{{Cinderella}} the animated film]], but no mention is given of his real name "Octavius," from which Augustus/Gus is a nickname of.

** ''Film/XMenDaysOfFuturePast'' is rather vague about why the Sentinels conquered all of humanity in the film's BadFuture, despite being designed solely to hunt and kill Mutants. The comic book storyline explains that it was a twisted case of GoneHorriblyRight: Bolivar Trask programmed his robots to stamp out the Mutant race by any means necessary, but didn't consider how many ordinary humans carried the recessive "X-gene" that causes mutation; the Sentinels proved to be a little too good at their jobs, and eventually began building concentration camps for processing and detaining all humans with the X-gene, killing any humans who tried to stop them.

** The movie never explains how the distinctive blots on Rorschach's mask constantly shift and move, leaving some viewers to wonder how a dirt-poor street vigilante got his hands on such a seemingly advanced piece of synthetic fabric (especially since the story takes place in the 1980s, when such materials weren't widely available). The book explains that it's one of many synthetic materials developed through Doctor Manhattan's experiments with physical matter, and Rorschach acquired it when he was working in a garment shop before becoming a crime-fighter.[[note]] The fabric was originally intended to be used in a dress, but the buyer returned it because she didn't like how it looked. Rorschach claims that the buyer was none other than [[https://en.wikipedia.org/wiki/Murder_of_Kitty_Genovese Kitty Genovese]], whose brutal murder partly inspired his black-and-white view of morality.[[/note]]

** The films don't really elaborate on why the way to get through the Doors of Durin and into Moria is [[ThePasswordIsAlwaysSwordfish simply to say the elvish word for "friend"]], other than Frodo referring to it as a "riddle" (which it isn't, really; it's more of a trick question that Gandalf had misinterpreted and was overthinking). In the books, this is elaborated on a little more: the Doors of Durin were created in a time of great peace, and therefore simply naming yourself to be a friend was enough to be allowed in. The password is in an elvish language (specifically, Sindarin) rather than the dwarfish Khuzdul because at the time, the dwarves had a close friendship with the elves living nearby. Funnily, this was something the far more truncated [[WesternAnimation/TheLordOfTheRings Bakshi version]] managed to explain properly.

'''Gimli:''' Those were happier times.\\

-->'''Legolas:''' So, all you had to do was say, "friend," and enter.\\

** For that matter, very little about [[BigBad Sauron]] is ever explained, leaving casual viewers who haven't read the books to wonder who (and what) he actually '''is''', and how he became so dangerously powerful. In a nutshell: he's one of several lesser deities called ''Ainur'' (specifically, a lesser order of Ainur called ''Maiar'') who serve Middle Earth's supreme creator god ''Eru Ilúvatar''. Long before the events of the story, he went rogue and joined another rogue Ainu, a Vala called Melkor (aka "Morgoth") as his [[TheDragon right-hand man]], and later [[DragonAscendant took up Morgoth's cause]] after he was defeated and exiled in his attempt to destroy the world. In other words: he's a FallenAngel in the vein of Lucifer.

** One issue that is routinely brought up as though it's a plot hole is "Why didn't the Fellowship just use the eagles and fly the One Ring to Mount Doom, then drop it in from the air?" There are a number of reasons in the books that explain why. The Eagles are forbidden by their creator from intervening directly in the War, so they won't shepherd the Ring themselves. They also would be just as likely to be tempted to take the Ring for themselves as any other sentient creature. The most obvious reason is that the whole point of the Fellowship is to avoid detection, and a flock of eagles would bring all of Sauron's forces down on their heads. For all these reasons, the Eagles are only free to arrive once the Ring is gone and Sauron is defeated. Another factor is that their power is greatly increased in the movies; while their arrival did turn the tide in the book it was the assembled armies of their entire race intervening (which had been established to be mustering much earlier), not just four guys.

* The novel ''Literature/WhoCensoredRogerRabbit'' (which ''Film/WhoFramedRogerRabbit'' is based on) has a TwistEnding that explains the seemingly implausible pairing of Jessica and Roger: [[spoiler:the MacGuffin is actually a magic lamp containing a genie, which granted Roger two wishes--one of which was to marry Jessica]]. As the plot of the novel is completely different from the film, however, the movie's version of the Jessica/Roger relationship is simply treated as some strange, funny case of DeliberateValuesDissonance between humans and toons.

* The novel ''Literature/WhoCensoredRogerRabbit'' (which ''Film/WhoFramedRogerRabbit'' is based on) has a TwistEnding that explains the seemingly implausible pairing of Jessica and Roger: [[spoiler:the {{Macguffin}} is actually a magic lamp containing a genie, which granted Roger two wishes--one of which was to marry Jessica]]. As the plot of the novel is completely different from the film, however, the movie's version of the Jessica/Roger relationship is simply treated as some strange, funny case of DeliberateValuesDissonance between humans and toons.

* ''Film/AScannerDarkly'':

** For that matter, very little about [[BigBad Sauron]] is ever explained, leaving casual viewers who haven't read the books to wonder who (and what) he actually '''is''', and how he became so dangerously powerful. In a nutshell: he's one of several lesser deities called ''Valar'' (specifically, a lesser order of Valar called ''Maiar'') who serve Middle Earth's supreme creator god ''Eru Ilúvatar''. Long before the events of the story, he went rogue and joined another rogue Valar called Melkor (aka "Morgoth") as his [[TheDragon right-hand man]], and later [[DragonAscendant took up Morgoth's cause]] after he was defeated and exiled in his attempt to destroy the world. In other words: he's a FallenAngel in the vein of Lucifer.

* In ''Film/EdgeOfTomorrow'', soldiers use variety of guns but Rita Vrataski uses a CoolSword instead. Why she and only she is using a melee weapon is never explained. ''LightNovel/AllYouNeedIsKill'' from which the movie was adapted explains why. Guns have limited ammo which means no matter how good Rita will get she can only kill so many aliens in a single battle, and a melee weapon removes this limitation. On the other hand it's DifficultButAwesome to use and the only reason why Rita is capable of using it effectively is because she was stuck in GroundhogDayLoop and had as much time to train as she wanted.

* ''Film/TheHitchhikersGuideToTheGalaxy'' has Ford approaching Arthur with a shopping trolley filled with cans of beer and packets of peanuts. In the [[Literature/TheHitchhikersGuideToTheGalaxy book]] he explains that these are necessary for combatting TeleportationSickness but not here. With teleportation not being mentioned, we also aren't told how Arthur and Ford got on board the Vogon ship.