History AdaptationExplanationExtrication / HarryPotter

The ''Film/HarryPotter'' films from the third one onwards are full of these. One major reason why this series is so guilty of this is that the book series was still ongoing while the films were being made, so the scriptwriters had no idea what bits might provide pertinent background for future events, but there were also explanations being needed in the very same book/film that were still left out.

** Dumbledore's backstory is broadly hinted at -it's said that his father killed some muggles, he was once friends with Grindelwald, and he has a brother who isn't very fond of him and a sister who died young- but it's never explained how any of these events tie together, or how they are relevant to the plot or Dumbledore's character. A line from Harry during his conversation with Aberforth sums up the film's approach to the Dumbledore subplot.

** The movies never explain that Sirius willed his house - and by extension Kreacher - to Harry. So there's no explanation in ''Deathly Hallows Part 1'' when Kreacher obeys Harry's every command (despite his clear distaste for Ron and Hermione). Of course, if the director of ''[Film/HarryPotterAndTheOrderOfThePhoenix Order of the Phoenix]]'' had cut Kreacher entirely as he originally intended, it would have made the scene even ''more'' incomprehensible to people unfamiliar with the books... J.K. Rowling herself intervened during the development of the fifth film, cryptically telling the director--and by extension, readers--that Kreacher would be pivotal to the at-the-time-unreleased seventh book and needed to be kept in the movie.

** Several scenes which explained Voldemort's background are missing, in particular, the scenes relating to which items he made into Horcruxes, making the nature of the Horcruxes in the subsequent movies seem much more random. There also isn't a lot of explanation to why Dumbledore [[spoiler:knew a horcrux would be lurking in that cave in the Half-Blood Prince film. Yes, a photo of the very cave is seen in Tom Riddle's childhood, thus why Dumbledore would logically suspect its correct hiding place, but it's easy to miss and the "field trip" is not touched upon.]]

** The only witness who can corroborate Harry's account of [[spoiler:Voldemort returning]] is Barty Crouch Jr. In [[Literature/HarryPotterAndTheGobletOfFire the book]], the malicious/incompetent Minister for Magic [[spoiler:brings a dementor to defend him, which [[FateWorseThanDeath sucks out Crouch's soul]]]], leading to Harry being disbelieved for most of the [[Literature/HarryPotterAndTheOrderOfThePhoenix fifth book]]. [[spoiler:Barty Crouch Jr. getting his soul sucked out]] is not shown or alluded to in the fourth film, leading a savvy viewer to wonder why nobody believes Harry in the [[Film/HarryPotterAndTheOrderOfThePhoenix fifth film]].

** The Dementors attacking Harry at the beginning of [[Literature/HarryPotterAndTheOrderOfThePhoenix the book]] is largely suspected to be thanks to Voldemort commanding them now, only to be revealed that Umbridge sent them - hoping to silence Harry or discredit him further. In the film, Umbridge never confesses to it - though she does look quite guilty when delivering her line about Dumbledore suggesting a Ministry member ordering the attack. Ultimately, the film never directly addresses who sent the Dementors after Harry.

** The only witness who can corroborate Harry's account of [[spoiler:Voldemort returning]] is Barty Crouch Jr. In [[Literature/HarryPotterAndTheGobletOfFire the book]], the malicious/incompetent Minister for Magic [[spoiler:brings a dementor to defend him, which [[FateWorseThanDeath sucks out Crouch's soul]]]], leading to Harry being disbelieved for most of the [[Literature/HarryPotterAndTheOrderOfThePhoenix fifth book]]. Barty Crouch Jr. [[spoiler:getting his soul sucked out]] is not shown or alluded to in the fourth film, leading a savvy viewer to wonder why nobody believes Harry in the [[Film/HarryPotterAndTheOrderOfThePhoenix fifth film]].
** Likewise, people who have not read the books would think that Barty Crouch Jr. would fit under ChuckCunninghamSyndrome, given his absence from later films. Most of what he does is also left out - most blatantly, Barty Sr.'s corpse is taken out of the woods, but they never bring up the subject again.

The ''Film/HarryPotter'' films from the third one onwards are full of these. One major reason why this series is so guilty of this is that the book series was still ongoing while the films were being made, so the scriptwriters had no idea what bits might provide pertinent background for future events... but an explanation being needed in the very same book/film certainly didn't stop them from leaving it out.

** In both [[Literature/HarryPotterAndThePhilosophersStone the book]] and the film, Harry receives the Cloak of Invisibility on Christmas Day with a mysterious anonymous note telling him, ''"Your father left this in my possession before he died. It is time it was returned to you. Use it well."'' At the end of the book when Harry is in the Hospital Wing, Dumbledore reveals that he was the one who gave Harry the cloak. This explanation is left out of the film, nor is it brought up again in later films. While a non-reader could still make the guess that it was Dumbledore, the films ultimately leave it ambiguous.

** In both [[Literature/HarryPotterAndThePhilosophersStone the book]] and the film, Harry receives the Cloak of Invisibility on Christmas Day, with a mysterious anonymous note telling him, ''"Your father left this in my possession before he died. It is time it was returned to you. Use it well."'' At the end of the book when Harry is in the Hospital Wing, Dumbledore reveals that he was the one who gave Harry the cloak, whereas this explanation is left out of the film, nor is it brought up again in later films. While a non-reader could still make the guess that it was Dumbledore, the films ultimately leave it ambiguous.

* ''Film/HarryPotterAndTheChamberOfSecrets'':

** In [[Literature/HarryPotterAndTheChamberOfSecrets the book]] Harry, hiding in a cupboard in a Diagon Alley shop, overhears a conversation that becomes crucial in a later book. In [[Film/HarryPotterAndTheChamberOfSecrets the movie]], he still enters the shop, gets his arm caught by one of the shop's products, and then immediately leaves, making the scene rather pointless. Harry does overhear the conversation in the extended version of the film.

** The movie adaptation of never bothered to explain that the Marauders were [[spoiler:James Potter, Remus Lupin, Sirius Black, and Peter Pettigrew]]. This makes Lupin's sudden knowledge of exactly what the Marauder's Map does inexplicable, as well as Sirius instantly knowing what the map is when it's brought up later on in the film. Besides, it leaves the map itself a silly unexplained plot device out of nowhere instead of something perfectly intertwined in the rest of the story. Harry dropping Sirius' nickname in the 5th film (as well as Pettigrew being called by his) also comes out of nowhere without the Marauder backstory.
** The movie also never explains how Sirius Black escaped from Azkaban, but leaves in that it's a mystery how he escaped, as no one else ever has while [[Literature/HarryPotterAndThePrisonerOfAzkaban the book]] gives the readers an explanation for how he managed it.

** The only witness who can corroborate Harry's account of [[spoiler:Voldemort returning]] is Barty Crouch Jr. In [[Literature/HarryPotterAndTheGobletOfFire the book]], the malicious/incompetent Minister for Magic [[spoiler:brings a dementor to defend him, which [[FateWorseThanDeath sucks out Crouch's soul]]]]. Harry is disbelieved for most of the fifth book. In the film, this isn't brought up, leading a savvy viewer to wonder why nobody believes Harry.
** Additional one is the fact that Harry gets his winnings from the Triwizard Tournament then gives them to the twins because "people are going to need a laugh soon." This gives them the funding for the (otherwise dirt poor) Weasleys to start the shop once they quit school. With the films they just suddenly manage to make enough in a few short months to have a big shop already established in Diagon Alley.

** The book mentions that Hogwarts is under powerful magical protections, making portkeys ineffective, but those protections are removed on the grounds of the trials, including the portkey inhibitor. This is actually the reason Voldemort's plan includes enlisting Harry to the tournament : because it's the only way to get him to touch a portkey to bring him to the cemetary. In the movie, none of that is explained, so the plan just seems stupid and convoluted when Crouch Jr could just have called Harry into his office and handed him a portkey.

** The Dementors attacking Harry at the beginning of [[Literature/HarryPotterAndTheOrderOfThePhoenix the book]] is largely suspected to be thanks to Voldemort commanding them now, only to be revealed that Umbridge sent them - hoping to silence Harry or discredit him further. In the film, Umbridge never confesses to it - though Imelda Staunton does look quite guilty when delivering her line about Dumbledore suggesting a Ministry member ordering the attack. So it's never said who sent the Dementors after Harry.

** Here, Harry's Occlumency lessons are ended when he reflects Snape's Legilimency back onto him and sees a very short memory of James and Sirius bullying him as a child; Snape then throws him out. This is incredibly petty and stupid given how important these lessons are, but it makes more sense in the book. Book!Snape doesn't mind Harry reflecting Legilimency this way; the lessons end when Snape leaves the room to deal with an emergency and while he's out Harry repays his implicit trust by looking into the Pensieve where Snape has stored his most private memories, and sees a much more humiliating (and, with hindsight, a much more personal) memory than the incredibly brief scene we get in the film.
** There a scene where Harry & co. are rounded up by Draco and his goons in Professor Umbridge's office. In the book, Luna and Ginny cause a ruckus as a distraction in the group's thought-out plan to sneak Harry into the office, and Malfoy takes Neville in for trying to stop him from taking Ginny, but in the movie they outright skip the planning scenes and don't even hint at the girls' involvement. Draco simply brings the three in, says "caught this one [Neville] trying to help the Weasley girl", without an explanation as to why Ginny and Luna were caught.

** Strangely inverted at the end when Snape reveals -- with every bit of dramaticism Alan Rickman can muster -- that he is, in fact, the half-blood prince whose annotated potions textbook Harry had been learning from on the side. While this does explain the way he's able to save Draco from a spell that Harry would think nobody would know, the film leaves out the follow-up scene in which Snape asks Harry for his potions textbook, which clues the audience in beforehand that Snape at least knows about the existence of the Half Blood Prince's book and instead, the audience is left wondering just why he's so damn ''serious'' about such a thing. That's because it's basically mentioned once in the movie; in [[Literature/HarryPotterAndTheHalfBloodPrince the book]] the search for who the "prince" really is acts as the ''main subplot'', getting quite nearly as much time as the main plot itself.
** Several scenes which explained Voldemort's background are missing, in particular, the scenes relating to which items he made into Horcruxes, making the nature of the Horcruxes in the subsequent movies seem much more random. There also isn't a lot of explanation to why Dumbledore [[spoiler:knew a horcrux would be lurking in that cave in the Half-Blood Prince film. Yes, a photo of the very cave is seen in Tom Riddle's childhood thus why Dumbledore would logically suspect its correct hiding place, but it's easy to miss and the "field trip" is not touched upon.]]

** The shard of the mirror Harry broke in the end of the book of ''Order of the Phoenix'' magically appears in the final films and is every bit as useful as it was in [[Literature/HarryPotterAndTheDeathlyHallows the book]] - but with no prior explanation.
** Remus and Tonks in a blink-and-you-miss-it scene where Tonks is apparently about to announce her pregnancy too, but is interrupted. Their relationship is not mentioned again, until a scene late into in Part 2 when Harry is magically aware of their son Teddy's existence.
** In the seventh film the question Lupin asks Harry to make sure he's not an impostor (what creature was in his office when Harry first visited) doesn't really make sense since Harry isn't shown in Lupin's office until the very end of the 3rd film and they spend all their scenes together out walking in the forest.
** The movies never explain that Sirius willed his house - and by extension Kreacher - to Harry. So there's no explanation in ''Deathly Hallows Part 1'', when Kreacher obeys Harry's every command (despite his clear distaste for Ron and Hermione). Of course, if the director of ''Order of the Phoenix'' had cut Kreacher entirely as he originally intended, it would have made the scene even ''more'' incomprehensible to people unfamiliar with the books... According to Potter lore, J.K. Rowling intervened during the development of the fifth film, cryptically telling the director--and by extension, readers--that Kreacher would be pivotal to the at-the-time-unreleased seventh book and needed to be kept in the movie.
** A scene explaining the Taboo (Ron mentions hearing about it in the Ministry) was cut from Deathly Hallows – Part 1, so it's never explained despite its effects showing up in two plot-critical moments (the book-verbatim Death Eater attack in the café, and a new change to the Lovegood house scene where Xenophilius says Voldemort's name to summon Death Eaters), making them seem like Diabolus ex Machina rather than a jinx. It also saves the writers some trouble, because through the movies they have been downright spotty about wizards saying Voldemort's name, a feature which was important in the books.
** At the beginning of the eighth film, which adapted the second half of the seventh book, the main characters attempt to break into the wizard bank Gringotts by having Hermione impersonate Bellatrix Lestrange using Polyjuice Potion. At the end of the previous film, they had defeated Bellatrix and obtained her wand (which can work like ID in the wizarding world). In the book, it's explained that the Gringotts staff probably know that Bellatrix was attacked and ask Hermione for her wand as a trap (if she has it, it proves that she's a fake Bellatrix). In the film, this is not explained at all, but there is still a huge amount of dramatic tension when the Gringotts goblin asks for the wand, leaving the viewer to wonder why everyone is acting worried when they clearly recovered the wand at the end of the last film.

** There a scene where Harry & co. are rounded up by Draco and his goons in Professor Umbridge's office. In the book, Neville, Luna, and Ginny cause a ruckus as a distraction in the group's thought-out plan to sneak Harry into the office, but in the movie they outright skip the planning scenes and don't even hint at the trio's involvement. Draco simply brings them in, says "we caught 'em", without an explanation as to why they were caught.

** The book mentions that Hogwarts is under powerfull magical protections, making portkey ineffective, but those protections are removed on the grounds of the trials, including the portkey inhibitor. This is actually the reason Voldemort's plan includes enlisting Harry to the tournament : because it's the only way to get him to touch a portkey to bring him to the cemetary. In the movie, none of that is explained, so the plan just seems stupid and convoluted when Crouch Jr could just have called Harry into his office and handed him a portkey.

** The film leaves out most of the background information about Arthur Weasley and Lucius Malfoy, including what Malfoy stood to gain by giving Ginny the diary that would force her to open the Chamber of Secrets -Namely, that Arthur had enacted several muggle-protection laws Malfoy didn't like and kept having their home searched for dark artifacts he was (rightly) convinced Malfoy was hiding. Giving Ginny the diary not only got one such relic out of his possession, but had she been discovered as the culprit behind several violent attacks on muggleborn students, it would have destroyed Arthur's career and given Malfoy the leverage he needed to get the laws repealed (the fact that [[FantasticRacism he got to hurt some mudbloods along the way]] was probably a nice bonus too). None of this is explained in the film, making it look like he did it [[ForTheEvulz just to be a dick]] (unless, perhaps, [[spoiler: the spirit in the Diary told him to himself]]). Which, to be fair, is still kind of in-character, but it does rob him of some of his MagnificentBastard status.

** While the film does mention that ownership of all three Deathly Hallows makes one master of death and explains Harry's ownership of the elder wand and resurrection stone, Death's invisibility cloak is never mentioned after the story is told, and it's never made clear that Harry's invisibility cloak is the same one. This makes Voldemort's failure to kill Harry in the forest seem like a contrivance rather than happening due to the Deathly Hallows.

** In the book Harry, hiding in a cupboard in a Diagon Alley shop, overhears a conversation that becomes crucial in a later book. In [[Film/HarryPotterAndTheChamberOfSecrets the movie]], he still enters the shop, gets his arm caught by one of the shop's products, and then immediately leaves, making the scene rather pointless. Harry does overhear the conversation in the extended version of the film.

** The movie also never explains how Sirius Black escaped from Azkaban, but leaves in that it's a mystery how he escaped, as no one else ever has.

** The only witness who can corroborate Harry's account of [[spoiler:Voldemort returning]] is Barty Crouch Jr. In the book, the malicious/incompetent Minister for Magic [[spoiler:brings a dementor to defend him, which [[FateWorseThanDeath sucks out Crouch's soul]]]]. Harry is disbelieved for most of the fifth book. In the film, this isn't brought up, leading a savvy viewer to wonder why nobody believes Harry.

** The Dementors attacking Harry at the beginning of the book is largely suspected to be thanks to Voldemort commanding them now, only to be revealed that Umbridge sent them - hoping to silence Harry or discredit him further. In the film, Umbridge never confesses to it - though Imelda Staunton does look quite guilty when delivering her line about Dumbledore suggesting a Ministry member ordering the attack. So it's never said who sent the Dementors after Harry.

** Strangely inverted at the end when Snape reveals -- with every bit of dramaticism Alan Rickman can muster -- that he is, in fact, the half-blood prince whose annotated potions textbook Harry had been learning from on the side. While this does explain the way he's able to save Draco from a spell that Harry would think nobody would know, the film leaves out the follow-up scene in which Snape asks Harry for his potions textbook, which clues the audience in beforehand that Snape at least knows about the existence of the Half Blood Prince's book and instead, the audience is left wondering just why he's so damn ''serious'' about such a thing. That's because it's basically mentioned once in the movie; in the book the search for who the "prince" really is acts as the ''main subplot'', getting quite nearly as much time as the main plot itself.

** The shard of the mirror Harry broke in the end of the book of ''Order of the Phoenix'' magically appears in the final films and is every bit as useful as it was in the books - but with no prior explanation.

** The reason why Harry doesn't realize Bathilda Bagshot is possessed by Nagini is because he is a Parselmouth — snake-talk appears to him as human speech, unlike the gibberish it is to others. In the movie, we hear him and possessed Bathilda talk in Parseltongue from an observer's viewpoint.

** The film leaves out most of the background information about Arthur Weasley and Lucius Malfoy, including what Malfoy stood to gain by giving Ginny the diary that would force her to open the Chamber of Secrets -Namely, that Arthur had enacted several muggle-protection laws Malfoy didn't like and kept having their home searched for dark artifacts he was (rightly) convinced Malfoy was hiding. Giving Ginny the diary not only got one such relic out of his possession, but had she been discovered as the culprit behind several violent attacks on muggleborn students, it would have destroyed Arthur's career and given Malfoy the leverage he needed to get the laws repealed (the fact that [[FantasticRacism he got to hurt some mudbloods along the way]] was probably a nice bonus too). None of this is explained in the film, making it look like he did it [[ForTheEvulz just to be a dick]]. Which, to be fair, is still kind of in-character, but it does rob him of some of his MagnificentBastard status.

-->'''Harry''': I'm not interested in what happened between you and your brother.

** The shard of the mirror Harry broke in the end of the book of ''Order of the Phoenix'' magically appears in the final films and is every bit as useful as it was in the books - but with no prior explanation.

** Dumbledore's backstory is broadly hinted at -it's said that his father killed some muggles, he was once friends with Grindelwald, and he has a brother who isn't very fond of him and a sister who died young- but it's never explained how any of these events tie together, or how they are relevant to the plot or Dumbledore's character.

* In ''Literature/HarryPotterAndTheChamberOfSecrets'', Harry, hiding in a cupboard in a Diagon Alley shop, overhears a conversation that becomes crucial in a later book. In [[Film/HarryPotterAndTheChamberOfSecrets the movie]], he still enters the shop, gets his arm caught by one of the shop's products, and then immediately leaves, making the scene rather pointless. Harry does overhear the conversation in the extended version of the film.

* The ''Film/HarryPotter'' films from the third one onwards are full of these. One major reason why this series is so guilty of this is that the book series was still ongoing while the films were being made, so the scriptwriters had no idea what bits might provide pertinent background for future events... but an explanation being needed in the very same book/film certainly didn't stop them from leaving it out.

Oh boy, here we go:

* The ''Order of the Phoenix'' film keeps the plot point that no-one believes Harry about Voldemort. But, because some plot points were edited out of the ''Goblet of Fire'' film and never reinstated, viewers never know ''why'' no-one believes Harry beyond Fudge's complete denial of the facts and using Sirius as TheScapegoat.
* Speaking of ''Goblet of Fire'', people who have not read the books would think that [[spoiler:Barty Crouch Jr.]] would fit under ChuckCunninghamSyndrome, given his absence from later films. [[spoiler:[[AndIMustScream His soul was sucked out by a Dementor]].]]
* The Fidelius charm is never introduced in the films, so certain things go unexplained.
* A scene explaining the Taboo (Ron mentions hearing about it in the Ministry) was cut from ''Deathly Hallows – Part 1'', so it's never explained despite its effects showing up in two plot-critical moments (the book-verbatim Death Eater attack in the café, and a new change to the Lovegood house scene where Xenophilius says Voldemort's name to summon Death Eaters), making them seem like DiabolusExMachina rather than a jinx. It also saves the writers some trouble, because through the movies they have been downright spotty about wizards saying Voldemort's name, a feature which was important in the books.
* Fudge is never shown to be directly dismissed. The Minister of Magic makes no appearance in the sixth movie, and the seventh just puts a new Minister in office without explanation, except for the ''small'' fact that one of the headlines seen at the end of the fifth film reads "[[http://harrypotter.wikia.com/wiki/File:Minister_to_Resign.JPG Minister to resign?]]".
* The reason why Harry doesn't realize [[spoiler:Bathilda Bagshot is possessed by Nagini]] in the seventh film is because he is a Parselmouth -- snake-talk appears to him as human speech, unlike the gibberish it is to others. In the movie, we hear him and [[spoiler:possessed Bathilda]] talk in Parseltongue from an observer's viewpoint.
* The scene in ''Half-Blood Prince'' where Dumbledore explains what the Horcruxes might be is cut. Creator/CleolindaJones' [[http://m15m.livejournal.com/20930.html Movies in 15 Minutes]] [[TheAbridgedSeries abridgement]] lampshades this by claiming You-Know-Who was just being smart.
* The material is re-introduced in several ways in ''Hallows Part 2'': merely knowing that Bellatrix was afraid of what they might have taken from her vault lets him know a Horcrux is there, and once they get inside, Harry's scar gives him a SpiderSense, letting him track down the object in question ([[spoiler:a cup, theoretically Helga Hufflepuff's but maybe anybody's]]). This same ability allows him to [[spoiler:learn that Nagini is a Horcrux, and another is connected to Rowena Ravenclaw]], and later to sense the presence of [[spoiler:the diadem]] in [[spoiler:the Room of Requirement]], hidden [[spoiler:in a velvet jewel box instead of sitting on a warlock statue]].
* Dumbledore is set up over the course of ''Parts 1'' and ''2'' as being not as kind and fatherly as he appeared. Now, in the book, all of this finally comes together and Dumbledore is revealed to still have been a good man who in the end [[spoiler:essentially arranges Voldemort's downfall]]. But in the movie, most of [[spoiler:his conversation with Harry at King's Cross]] is cut, and the subplot is left dangling. (Conversely, most of the explicit references to Dumbledore's dark side, such as [[spoiler: his brief alliance with Grindelwald]] and [[spoiler: his complicity in the death of his sister]], don't get a mention either, so all that's left are a few vague hints of wrongdoing.)
* Remus and Tonks in a blink-and-you-miss-it scene in ''Deathly Hallows – Part 1'': Tonks is apparently about to announce her pregnancy too, but is interrupted. Their relationship is not mentioned again, until the resurrection stone scene when Harry is magically aware of Teddy's existence.
* Any scene pertaining to the introduction of the two-way mirrors is left out, leaving it to turn up apparently randomly at various points in the last few films. Its function is given an "explanation" in ''Deathly Hallows – Part 2'', but you are never told why Harry has it.