The main character or characters has amnesia in a situation which would be trivially easy to handle if they could remember how to deal with the situation, but is extremely dangerous because they can't.


For this trope to work; the character or object at hand must be completely oblivious to his/her capability to solve the current-tense conflict, or be so about the knowledge how to; followed with the ''base fact'' that said character once had the knowledge / ability to solve the issue.


Often a sign of writers desperate for plot ideas -- not always, [[TropesAreNotBad because there have been some good stories on these lines]], but usually. It's especially common in sci-fi and fantasy shows, because they have plenty of AppliedPhlebotinum lying around to explain the fact that [[LaserGuidedAmnesia the amnesia's so precise.]] It is also a [[PlotDevice Plot Device]] used in order to build up the melodrama for an explosive epilogue. Compare DramaPreservingHandicap, contrast ForgotAboutHisPowers.


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!!Examples

[[folder:Advertising]]
* A mid-80's Cocoa Puffs ad campaign guest-starred {{Popeye}} with the cereal's mascot Sonny the Cuckoo Bird. Popeye is trying to help Sonny escape the kids who constantly amuse themselves by tempting him to cave in to his Cocoa Puffs addiction. Popeye's ship runs aground and he gets hit on the head, forgetting all about spinach! Kids were asked to write in to remind Popeye of his secret weapon. Naturally, the sailor eventually remembers, but [[FamilyUnfriendlyAesop even spinach isn't strong enough to fight the addictive power of Cocoa Puffs!]]
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[[folder:Anime and Manga]]
* It happened to [[TheHero Duke Fleed]] in one of the manga versions of ''UFORoboGrendizer'' -one of the ''MazingerZ'' sequels-. In the first episode of the Gosaku Ota manga, Duke does not remember anything about his past since [[TheProfessor Dr. Umon]] had wiped his memory's out so he could live peacefully without remembering anything about his destroyed home and slaughtered family. When [[AlienInvasion the Vegans began their attacks]] the shock brought his memories back and he remembered he could, you know, put a stop to that.
* It also happened in the sequel to ''CuteyHoney'', another Creator/GoNagai creation. In the first episode of New Cutey Honey, she spends a long while running from the {{Mook}}s of the [[spoiler:apparent]] BigBad until she gets her memories back and remembers she can kick their sorry butts easily.
* Kaito in ''MermaidMelodyPichiPichiPitch'' could have saved both Lucia and Michal a lot of heartache and jealousy if he just remembered who he was and which one was his girlfriend.
* Happened to Lelouch in Episode 1 of ''CodeGeass R2''. He could have dealt with Britannia's attack with the help of La Resistance if he hadn't had his memories wiped, but instead of kicking Britannia's ass he spent the latter half of the episode running around. Uselessly.
** He more than makes up for it when he gets his memories back by [[spoiler: [[ItsGoingDown toppling a TOWER on top of his enemies]] while [[MagnificentBastard still managing to convince them that the amnesia hadn't been fixed.]] ]]
* ''Manga/MahouSenseiNegima'':
** Inverted with Yue in the "Magical World" arc: Her amnesia results in her being admitted to a prestigious school of magic and later to a group of magical knights, completely shielding her from anyone attempting to claim the huge bounty on her despite said knights serving as law enforcement personnel.
** Asuna Kagurazaka may turn out to be a straight, if unusually long-term, case: Her missing memories have so far been shown to include her own magical-combat abilities and her time being escorted by the Ala Rubra, and probably include more knowledge of Negi's father than anyone else has yet shared with him, all of which would be helpful to have as she, Negi, and the gang are on a quest to find Negi's father.
* The Stand ''Jail House Rock'' in the "Stone Ocean" part of ''Manga/JoJosBizarreAdventure'' takes advantage of this to an extreme degree. The Stand attenuates the victim's short-term memory to the point that they cannot retain more than three facts at any time. If the villain for instance shoots four bullets at Jolyne, at the point she notices the fourth one ''she'll forget they fired the first one''.
* Stop and think for a second about how much less story there would have been in ''RaveMaster'' if Elie had never lost her memories.
* In the ''Manga/DetectiveConan'' non-canon movie, ''Captured in Her Eyes'', Ran witnesses someone nearly killing a police officer friend of hers and, as a result, undergoes a severe case of TraumaInducedAmnesia. This puts her in danger in two ways, when the killer decides to off her because [[HeKnowsTooMuch she knows too much]]. The first is that while she saw the identity of the killer, her amnesia means she can't recognize him [[spoiler:even though she repeatedly sees him when he treats her as her doctor]]. The second is that she completely forgets her knowledge of fighting, so she's more or less defenseless when the killer makes several attempts on her life. [[spoiler:When she ''does'' get her memories back, she gives the killer an ''epic'' beatdown to make up for it.]]
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[[folder:Comics]]
* In a ComicBook/BlackPanther Arc Photon, once leader of ComicBook/TheAvengers, had kind of forgotten who she was and how to use her powers. This was unfortunate as the city she was in was having a [[ZombieApocalypse vampire apocalypse]], a situation her light based powers were ideal for dealing with. What's worse is that most of the other heroes don't really know her or what she's capable of and therefore aren't trying to get her to remember.
** Matter of fact, by the end of the story she still doesn't have her memories back (despite being a little better with her powers). [[ContinuityOverlap Somewhere]] down the line she eventually does lose her amnesia [[ComicBook/NextWave though]].
* Comicbook/MsMarvel's origin involved the character not knowing she was a superhero and having blackout spells whenever the titular character would go out and do some superheroin', but was "just an ordinary woman" when she wasn't. Similar to Harry and ComicBook/NormanOsborn in the ''Spider-Man'' comics not knowing they were Green Goblin from time to time.
* Rose Forrest/The Thorn in Creator/DCComics' ''Rose And Thorn'' had the same deal. In current continuity, Rhosyn Forrest ''knows'' about Thorn, but doesn't trust her, and certainly can't do the things she does.
* In one issue of the Franchise/{{Batman}} comics, Bruce forgot that he was Batman. ComicBook/{{Nightwing}} and Robin had to team up to protect him and get him to remember.
* ComicBook/DisneyDucksComicUniverse: In the Creator/DonRosa comic "Forget It!", Magica de Spell puts a curse on Scrooge and Donald Duck, which has the following effect: whenever they hear their names spoken in conjunction with another thing, they immediately forget the thing in question ever existed. Thus, they can't even open a door, because she makes them forget what doors are. And this is just the beginning...
* In one ''ComicBook/JonahHex'' story, Jonah is buried by a rockslide while dressed in the clothes of a preacher. Digging himself out, he cannot remember who he is. Finding a letter addressed to the preacher in his pocket, he assumes that he is the preacher and takes the preacher's new posting as an army chaplain.
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[[folder:Fanfiction]]
* In the ''[[Anime/YuGiOh Yu-Gi-Oh!]]'' fanfic, ''[[FanFic/ThePrincessAndTheDragon The Princess and the Dragon]]'', Mai is under a spell that makes her forget Jou and Ishtar [[note]] Yami Marik [[/note]], as well as Jean Claude's true identity. Her ignorance puts her in grave peril.
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[[folder:Films]]
* Inverted in ''Film/ThirtySixHours1965''. If the main character only knew that he did ''not'' have amnesia, but was rather being subjected to an elaborate deception, his course of action would be clear: he must keep secret from the Nazis who have captured him the time and location of the D-Day landings. Unfortunately he thinks the people all around him are doctors and that six years have passed that he can't remember.
* ''Film/{{Memento}}'': At one point, the amnesiac Leonard (who cannot hold onto any new memories for more than 20 minutes) assumes he's chasing a man until said man starts shooting at him, at which point he realizes that the man is chasing ''him.'' He escapes, but upon having reached the hotel room of the man, he hides in the bathroom and prepares to ambush his quarry with a wine bottle. However, he forgets why he is there as well and assumes he was about to take a shower, leaving him unprepared for when the enemy does arrive.
* ''Film/MenInBlack II'', where MIB needs the memory-wiped Kay to come out of retirement to deal with the crisis at hand. And when he remembers being in MIB, it turns out he wiped his memory of the critical event, so they're still in trouble.
* In the Dana Carvey film ''CleanSlate'', the protagonist is a detective suffering from amnesia who's supposed to testify in court but can't remember the details of the case he was working on.
* ''Film/StarTrekInsurrection'''s plot is kick-started after Data is damaged in a way where he retained no conscious memory, and was driven only by "moral subroutines."
* Subverted in TheLongKissGoodnight when a hit man shows up at Sam's house and she handily kicks his ass, without knowing quite how she's doing it.
* In the film ''Mirage'', the main character is unaware he has amnesia at all. His mind, to cover the amnesia, has filled in the blanks. This becomes a problem when hired killers pursue him, also unaware he has amnesia and can't give him the information they want.
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[[folder:Literature]]
* In ''Literature/{{Animorphs}}'' Megamorphs #1: The Andalite's Gift, Rachel endures [[TapOnTheHead head trauma]] and loses her memory. As a result, she spends most of the book lost in the woods since she can't remember who she is or that she can morph to help find her way out.
* In the fourth ''Literature/ArtemisFowl'' book, [[spoiler: Opal Koboi has escaped and is getting her revenge several people, including Holly Short and the title character. Unfortunately for Artemis, he had been [[WistfulAmnesia mindwiped]] and remembers absoultely nothing about Fairies, which leads to Holly having to take charge when the two have to escape a group of trolls.]]
* In Cornell Woolrich's "The Black Curtain" a man is struck on the head and gets off the ground unaware that he's had amnesia for the last two years. People start chasing him but he has no idea why, or where he has been.
* The main premise of ''Literature/AWindNamedAmnesia'' where [[spoiler:aliens cause]] a world-wide memory loss affects everything from animals and humans to computers with only ''one'' cyborg not being affected, causing {{the end of the world|AsWeKnowIt}}.
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[[folder:Live Action TV]]
* ''Series/BuffyTheVampireSlayer'', "Tabula Rasa" - there are elements of this in "Halloween", too.
* ''Series/StargateAtlantis'', "Tabula Rasa"
* The long Lois amnesia plot and the Superman amnesia story in ''Series/LoisAndClark'' (the latter of which was a remake of the Superman amnesia story in ''Series/TheAdventuresOfSuperman'').
** Specifically, an asteroid is on a collision course with Earth, so the government asks Super to destroy it. He ends up flying at it with high speed and slams into the rock. While the asteroid is destroyed, Supes is thrown to the ground and loses his memories from the impact. So when it turns out a large enough piece of the asteroid is still on a collision course, Superman is nowhere to be found, only an amnesiac Clark whom his parents try to convince is Superman (by hitting him with a baseball bat and throwing him off the roof). Unfortunately, Supes has [[RememberedICouldFly forgotten how to use his powers]] until the very end of the episode, when he flies up and gently pushes the piece of the asteroid away.
* Played with in ''Series/{{Dollhouse}}'' episode 4, "Gray Hour". The whole theme of the series revolves around certain characters which are given amnesia and given new personalities almost twice an episode. Then halfway through this episode, [[spoiler: one of these actives loses her memory in the middle of a mission for real.]] From there this trope is played straight.
** Interestingly, the Dollhouse's solution to the crisis is pretty ingenious. They give the same personality to a different Active and have her guide Echo by phone.
* Appears several times in ''Series/StarTrekTheNextGeneration''. In "Conundrum", the entire crew of the Enterprise have their memories erased by aliens, in order to trick them into attacking the aliens' enemies. In "Thine Own Self", Data wanders into a village on a primitive planet, with no knowledge of who or what he is, bearing a case full of radioactive metal fragments; not knowing the danger, he sells the fragments to the local blacksmith.
** There's also the TNG episode "Clues" in which the crew of the Enterprise discovers evidence that their memories and records have been tampered with and backtracks...[[AmnesiaLoop only to discover that one of the things they've forgotten is that they had]] ''[[AmnesiaLoop agreed]]'' [[AmnesiaLoop to having their minds wiped in the first place]].
* In the ''[[Series/StarTrekTheOriginalSeries TOS]]'' episode ''The Paradise Syndrome'', the danger was that the amnesiac character (Kirk) had forgotten that there ''was'' a danger. Hilariously, the main thing he knew that (once remembered) saved the day was learned literally second before he lost his memory.
* ''Series/{{Charmed}}'': Prue becomes a teenager and loses her memories in "Be Careful What You Witch For", getting her in trouble with an evil dragon warlock. Piper loses her memories in "Valhalley of the Dolls", causing explosions galore. Leo loses his memories in "The Seven Year Witch", making it almost impossible to make his way home and return to Piper and his sons.
* Used in an episode of ''Series/MyHero'' in which Thermoman, whose powers include erasing people's memories, inadvertently erases his own memory of being Thermoman. This, of course, conincides with the discovery of a giant meteor hurtling towards the Earth.
* Occurs in at least three ''Series/MacGyver'' episodes, where Mac loses his memory due to being drugged, shot in the head, etc.
* Phelps loses his memory in the middle of a mission in ''Series/MissionImpossible'', when he's supposed to walk into a trap in order to snare the villain; to complicate things, the person who tries to help him assumes he's the person he had been pretending to be.
** Shannon loses her memory too in the second series. To complicate things ''further'', the guy she was supposed to fool proposes to her...
* Inverted in ''Series/HoneyIShrunkTheKids'', after losing her memories of everything that happened after she was 16, Diane is able to easily win a court case that she couldn't identify with because she was a grown-up.
* Part of the central premise of ''QuantumLeap'': Sam Beckett was an absurdly intelligent polymath who bordered on being a GodModeSue, but the effect that time travel is constantly having on his memory prevents him from figuring out a way to get back home.
* On ''Series/{{Angel}}'' [[spoiler: the [[LossOfIdentity memory-wiped]] Connor is fighting Sahjhan and losing decisively until Wesley inadvertently returned some of his memories mid-fight. About 6 seconds later Sahjhan was decapitated.]]
** In another episode, the heroes regressed back to their teenaged selves. Most of them had little or no fighting experience, and so the team found themselves unusually vulnerable - in addition to wrongly figuring out what was going on.
* Happens a lot on ''{{Fringe}}'' with the character Walter Bishop, who can't remember science experiments he conducted before entering a mental hospital. Often this information is vital to the case they are trying to solve.
** It's revealed that the cause of the amnesia is [[spoiler:Walter agreeing to let his friend William Bell remove certain parts of his brain]].
* In early episodes of ''Series/{{Heroes}}'', the Niki/Jessica relationship somewhat similarly to Rose and Thorn from the Comics folder. Niki would wake up from a blackout and see a bunch of corpses strewn about, no idea how they got there.
* ''Series/DoctorWho'':
** In the two-parter [[Recap/DoctorWhoS29E8HumanNature "Human Nature"]]/[[Recap/DoctorWhoS29E9TheFamilyOfBlood "The Family of Blood"]], the Doctor turns himself human and puts his Time Lord memories into a watch in order to hide from the MonsterOfTheWeek. He intends for Martha to open the watch and give him his memories back when the aliens show up, but it gets stolen, leaving them all in danger.
** This is the main threat of [[spoiler:the Silents: you can only remember them when you're actually looking at them. As soon as you've looked away for even a couple of seconds, you forget what you saw.]]
* In the first ''Series/KamenRiderDenO'' movie, the shock of [[MyFutureSelfAndMe meeting his past self]] causes Ryotaro to develop amnesia of everything relating to the Imagin and his being Den-O, which means that for much of the movie they don't have access to Den-O's powers. [[spoiler:This becomes a major plot point in the story arc dealing with the fallout from the movie, where this temporary severing of their contracts causes Urataros, Kintaros, and Ryutaros to fade away and apparently "die".]]
* An episode of ''Series/SevenDays'' had terrorists give a bomber wing an order to destroy an American base (supposedly overrun). Since Frank temporarily lost his memory when traveling back, the good guys didn't contact the bombers until they were [[IrrevocableOrder past the official point of no return]]. They had to put the commander's pregnant wife on the phone to convince him.
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[[folder:Video Games]]
* Used in ''PhoenixWrightAceAttorney: Justice for All'' as an excuse to give [[HeKnowsAboutTimedHits a tutorial]] to players that never played the original game. In truth, Phoenix has all but solved the case when he gets clonked on the head and loses his memory.
** ''ApolloJustice'' uses this for a backstory mystery. [[spoiler:Were it not for Lamiroir's memory loss, she could have simply told Apollo and Trucy herself that she was their mother and that they were half-siblings.]]
** In ''Dual Destinies'', [[spoiler:the trauma of walking in on her mother's murder caused Athena to completely block it out. While she didn't see enough to figure out who the actual culprit was, it did mean that she began to suspect that she ''did'' commit the crime, as several others argued. Her memories of the event were able to turn up necessary details to figure out who committed the crime and why.]]
* Considering the sheer amounts of experience the protagonist from ''PlanescapeTorment'' would have had were it not for his amnesia, the entire game could be considered an example of the trope, especially seeing that [[spoiler: you start in the room with the entrance to TheVeryDefinitelyFinalDungeon.]]
* This is so common in InteractiveFiction in general as to be a DiscreditedTrope.
** The short IF story 9:05 is a particularly nice example.
* Used in ''VideoGame/BreakDown'', a game for Namco on the original Xbox, to great effect. It's also a subversion in that you're undergoing a cure for your amnesia by playing the game. The wacked out hallucinations, it turns out, are false memories. The part in the beginning where you're told that you promised to save someone then makes sense, as on the way back to an earlier point in the plot, you promise to save them. An earlier comment made by a scientist saying that she knew too much for someone who doesn't work there is explained when she doesn't know who you are and decides to help you save the Earth (by going back to an earlier part.) And the part where the penultimate boss asks "Motivation: Inconclusive. Derrick? Do you feel any different?" after he kidnaps the girl takes a new meaning (if it wasn't already the PUB's meaning)
* In ''Kagetsu Tohya'', the ''VisualNovel/{{Tsukihime}}'' sequel, Shiki has been made to forget about what his eyes can do [[spoiler:because if he can see death, he can see the world collapsing and Len will have to rewrite everything again]]. So he repeatedly comes upon circumstances that would be no big deal and then wonders why he thought he could deal with such a thing. Like being chained or locked out of a room. [[spoiler:Or knife fighting someone to the death.]]
* ''VideoGame/NetHack''. [[NintendoHard Just]]. [[EverythingTryingToKillYou Nethack]]. Amnesia (Mind flayer, or reading a scroll of amnesia) attacks can erase parts of the map, and, even worse, will unidentify some of the items you have formally identified (Wait, was the purple or the black potion the one of [[HealThyself extra healing]]? [[FamousLastWords I'll try the black!]] [[YetAnotherStupidDeath *fall asleep while under attack*]]
* ''VideoGame/AmnesiaTheDarkDescent'', appropriately enough. You wake up in a castle, with nothing but a note telling you to kill a man named Alexander. Too bad you don't remember how or why, or what the [[spoiler:Shadow]] is or how to escape it.
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[[folder:Web Comics]]
* ''Webcomic/BugMartini'' [[http://www.bugcomic.com/comics/amnesia/ subverts this trope]] (and all for the doctor's amusement).
* ''Webcomic/{{Freefall}}'': Florence gets into this. [[spoiler: Sam gets her out.]]
* In the ''Webcomic/SluggyFreelance'' story arc "Oceans Unmoving" [[spoiler:Bun-Bun has few memories of his previous trip to Timeless Space, so he doesn't know that all he and his past self have to do is leap into the Oceans Unmoving in order to return to the real world]]. Made a delicious flavor of ironic by the fact that he gave ''himself'' amnesia.
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[[folder:Web Original]]
* In ''WebVideo/WormtoothNation'', main character Sam kicks off the very first episode this way. His partner Dimitri abandons him after he's been "nixed" by "wormtooth gas" since he's now useless to the cause.
* In ''Literature/{{Worm}}'', Bonesaw of the Slaughterhouse Nine creates a plague that inflicts retrogade amnesia on the people infected. Skitter, the protagonist, is attempting to find and kill the last surviving members of the Nine after she and the Protectorate have managed to eliminate or neutralize the others, before the plague hits and they all end up fighting one another. It's at that point that she runs into Grue and Tattletale, her teammates, a handsome, older white man and a prepubescent girl. Except that, as the readers know but Taylor can't remember, Grue is black and both he and Tattletale are her age. Skitter's actually found Jack Slash and Bonesaw.
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[[folder:Western Animation]]
* A BottleEpisode of ''{{Sealab 2021}}'' has the crew trapped in a supply closet by a malfunctioning door. The only person who knows how to fix it suffers an amnesia-inducing blow to the head, then [[RunningGag keeps getting knocked out]].
* Danny goes through a [[BeCarefulWhatYouWishFor unique form of memory loss]] in ''WesternAnimation/DannyPhantom'' that also resulted in [[BroughtDownToNormal power loss]]. Very bad timing when there's a ghost getting more and more powerful by the minute.
* Subverted in ''WesternAnimation/KimPossible'': when she loses her memory, all she needs is someone to tell her she can kick ass and she does.
* The Pixar film ''WesternAnimation/FindingNemo'' has Dory, a fish with short-term memory loss. This is also one of the most realistic depictions of amnesia in fiction.
** When she does finally find Nemo, she doesn't immediately realize it since she forgot that she was helping his dad look for him.
* An episode of ''WesternAnimation/TheBatman'' has Bruce Wayne forget all about being Batman. While it doesn't take much for Alfred to remind him who he is, he still doesn't remember any of his training.
** There was an episode of ''WesternAnimation/BatmanTheAnimatedSeries'' where Bruce went undercover to investigate why homeless people were being kidnapped, and was himself kidnapped and ended up with amnesia. He was forced to work in a mine with all the other kidnap victims until he remembered who he was.
* [[TheAdventuresOfJimmyNeutron Jimmy Neutron]] goes through something like this in one of the early episodes when he "drains his brain" [[IntelligenceEqualsIsolation to make himself less hated in class.]] He drains it to the point where he is nothing more than a drooling idiot, just in time for a giant meteor to be found hurling toward their town. The meteor [[spoiler: was inadvertently directed toward Earth by Jimmy]] in the first place.
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