This is a classic FairyTale written by Creator/HansChristianAndersen, about a mermaid who seeks to become human.

In this tale, mermaids live for centuries but have no afterlife. The youngest mermaid of the royal family is allowed to go up to the surface once she turns 15, and for several years in a row she longingly drinks in the tales her older sisters tell her of what it is like up there. When her time comes, she rescues a human prince from a storm and falls in love with him.

She then makes a deal with the Sea Witch to become human, but at heavy cost. The Sea Witch grants her legs and inhuman grace, but it will feel painful to walk, as if she is always stepping on swords. The mermaid also gives her tongue as payment. If she can make the Prince fall in love with her and marry her, she can gain a share in his soul and be human all her life, but if he marries another, she will die at the next dawn after his wedding day.

The prince she loves finds her and, charmed by her grace, takes her in and makes her a sort of pet.

Then he is betrothed, and his intended bride turns out to be the temple maiden he fell in love with at first sight when she found him on the shore after the little mermaid rescued him from drowning. As the mermaid mourns, her sisters appear to her with a LastSecondChance -- she can kill the prince with the enchanted knife they give her and live out her centuries as a mermaid -- or she will die at dawn. Unable to murder the man she loves, the mermaid throws herself into the sea and dissolves into sea foam.

Andersen revised the tale twice, first to change the sad ending to a bittersweet one ([[WordOfGod which he said he intended from the beginning]]) where the mermaid becomes a "daughter of the air" who, after 300 years of good deeds, will [[EarnYourHappyEnding earn an immortal soul and go to Heaven]]. He then revised it again with more of a moral, where good and obedient children can shorten her sentence but disobedient ones will make it longer.

The story has been adapted several times, from ballets, to musicals, to the the 1989 hit Franchise/DisneyAnimatedCanon film, ''Disney/TheLittleMermaid''. The Disney version changed the ending to a HappilyEverAfter one, and several [[LostInImitation subsequent adaptations]] have followed suit.

It can be read online [[ here]].
!!Provides Examples Of
* AllLoveIsUnrequited: The mermaid loves the prince. The prince loves another woman.
* AnAesop:
** On the surface, it seems to say "[[LoveMakesYouDumb don't give up your life for love]]", as the Little Mermaid, who could swim around, do as she pleased, and live for 300 years under the sea, gave it all up because she fell in love and ended up dying because the prince loved someone else. However, since the reward for the path the Mermaid has taken is no less than an eternal life in heaven, it turns out that the message is quite the opposite -- LoveRedeems, and the theme of redemption through ordeal is unmistakable throughout the entire story.
** The latest ending makes the good deeds time adjust depending on whether children are being good or bad, with more time off for good behavior than time added for bad behavior.
* AgonyOfTheFeet: The Little Mermaid always feels like she is walking on blades, while she is human.
* AndIMustScream: You have sold your tongue and you feel like walking on blades every time you set a foot on ground without being able to complain about the pain. ''And the mermaid was said to be a gifted dancer.''
* AuthorAvatar: The story was written around the time a man Andersen loved romantically was getting married. There are claims that at the time, [[TearJerker Andersen was writing desperate letters that he didn't dare send, saying "I want to tell my love, but I cannot speak."]] Sound familiar?
* BecomeARealBoy: Mermaids live for three hundred years and then dissolve into sea foam, having no afterlife of any kind. The protagonist's ongoing wish, even prior to her falling in love with the prince, is to become a human and acquire immortality, though in many adaptations this is completely ignored in favor of emphasizing the love story.
* BittersweetEnding: The mermaid is given a choice to kill the prince and return home or not and turn to sea foam. She chooses the latter. However, after doing about 300 years of good deeds she can gain an immortal soul and go to heaven.
* CessationOfExistence: Mermaids live longer than humans but don't have an afterlife.
* CurseEscapeClause: The mermaid's older sisters trade their beautiful hair to the sea witch, in exchange for a chance to break the spell before it kills her -- if she plunges a magical knife into his heart and wets her feet with his blood, she will become a mermaid again and survive. She decides not to take it, though.
* CuteMute: The mermaid as a human.
* DarkIsNotEvil: Unlike the villainous Ursula from the Disney movie, the sea witch in the original tale was a neutral character. She had no ulterior motivations, her demand of the price was simply payment, and she gladly helped the mermaid's sisters in saving her, in addition to warning the mermaid of the deal's consequences.
* DealWithTheDevil: For an ordeal seeking the mere chance at ''gaining'' a soul, she gives up her centuries-long lifespan and her voice, while gaining human legs with extraordinary grace, but feel like she's ''walking on knives'', making her feet bleed every time she dances. If she marries the prince, she'll gain a soul, but if he marries someone else, she'll die permanently.
** Subverted, though, in that the "deal" was more or less an honest business transaction. The sea witch with whom she made the deal has no malevolent intentions; she clearly informs her of all the possible consequences beforehand, and later helps her sisters to try to save her.
* DiedHappilyEverAfter: The "good" ending is like this. When she refuses to kill the prince to regain her life as a mermaid, she instead becomes a spirit of the air, watching over children and waiting to gain a soul and go to heaven. (Well, at least it's better than the "she becomes sea-foam, eternally kissing the hull of the prince's ship" ending.) The ending is meant to be happy because mermaids naturally have no souls -- by sacrificing herself instead of her prince, the mermaid earned the right to [[EarnYourHappyEnding win her own soul]].
* EveryoneHasStandards: The Little Mermaid's sisters trade their hair for a knife that The Little Mermaid can use to kill the prince and use his blood to return herself to mermaid form. She cannot bring herself to do this (although it does help get her the chance to earn an immortal soul).
* EverythingsBetterWithPrincesses: The Little Mermaid, her sisters, and the girl who helped the prince after the Little Mermaid saves him.
* FashionHurts: The Little Mermaid had oysters attached to her tail by her grandmother to show her great rank.
-->'''Little Mermaid:''' But they hurt me so.\\
'''Grandmother:''' Pride must suffer pain.
* FriendOrIdolDecision: The mermaid has the choice to kill the prince and spare her life, or spare his at the cost of her own. She chooses the latter.
* GodivaHair: When she wakes up on shore, the little mermaid is naked, so she wraps her long hair around herself.
* HeavenAbove: The Little Mermaid describe {{Heaven}} as "that glorious world above the stars." This description of Heaven as sky also furthers the distance between the mermaid and the eternal realm, since land-dwelling humans are closer to the sky while the soulless mermaids are hopelessly far from those same stars. The story also describes angelic spirits as "Daughters of the Air."
* HeroicSacrifice: The mermaid is given the chance to kill the prince so she can continue her life, but she is unable to do so and dies herself in return.
** The mermaid's older sisters giving up their long, beautiful hair to the sea witch can be seen as a lesser example of this trope, too. In Hans Christian Andersen's time, a woman's beauty was her greatest treasure, and long, flowing hair was a vital trait of female beauty -- for a woman to have short hair was socially unacceptable and utterly taboo. Thus, the sisters giving up their long hair was basically a sacrifice of all of their earthly beauty and femininity.
* {{Irony}}: The Little Mermaid saved the prince, but left before he could see her. He actually fell in love with a girl at a nearby temple who helped him, who later turned out to be a princess from a neighboring kingdom -- and inadvertently condemned the poor mermaid to death.
* IWantMyBelovedToBeHappy: The mermaid chooses to spare the prince and accepts that he's happy with another woman.
* LastSecondChance: The mermaid can save her own life, even after the prince marries another, if she kills him on his wedding night.
* LikeBrotherAndSister: The prince's feelings towards the mermaid.
* LoveAtFirstSight: The mermaid towards the prince. [[AllLoveIsUnrequited The prince towards another girl.]]
* LoveRedeems: The reason why the mermaid chose to die rather than kill the prince.
* NamelessNarrative: No one is referred to by name, just their titles.
* NoAntagonist: The tale is a tragedy, but doesn't have a real villain.
* OurMermaidsAreDifferent: They can go to the surface when they are old enough, and lack immortal souls. They also live for 300 years.
* OurSoulsAreDifferent: Mermaids lack one, humans have one, and daughters of the air can gain one.
* PerfectlyArrangedMarriage: Although the Little Mermaid accidentally helps that along, the prince and the girl from the temple fall in love when it turns out she's a princess from a neighboring kingdom.
* RescueRomance: Tragically in the case of the mermaid; the prince she rescues doesn't love her and instead falls for the girl he ''thinks'' was his rescuer.
* SecretTestOfCharacter: It's implied that the only reason the Little Mermaid does not dissolve into sea-foam at the end is that she refused to kill the prince. Killing him would have lost her her chance at an immortal soul forever.
* SolitarySorceress: The Sea Witch lives by herself in a dangerous part of the ocean. Unlike in the [[Disney/TheLittleMermaid Disney adaptation]], here, she's a TrueNeutral character who tells the mermaid about every negative consequence her spell has.
* TakeAThirdOption: Either the prince must marry the mermaid, or she will die at the next sunrise if he marries another woman. With the sea witch's help, her sisters try to give her an option that will save her -- but it would involve killing the prince, so she doesn't take it.
* TheSoulless: Mermaids have no soul.
* SpeciesSpecificAfterlife: Humans are the only animals with souls. Mermaids cease to exist when they die. The titular mermaid is horrified by this. She finds out that mermaids can gain a soul (and thus have an afterlife) if they marry a human. As a result, the little memaid tries to marry a prince.
* TongueTrauma: The Little Mermaid has her tongue cut out by the sea witch as part of the deal.
* TooGoodForThisSinfulEarth: The innocent and sweet mermaid who sacrifices her undersea life for love ends up giving up the boy she loves and sacrificing herself instead. However, the story makes it clear throughout that she doesn't have a soul -- and upon her death, she is given a purgatorial afterlife where she might, with hard work and dedication, win a soul and go to heaven. So after her death, she begins to work her way up to Too Good For This Sinful Earth. Sad, but not hopeless -- which could well be the point.
* TraumaticHaircut: The mermaid's older sisters have their long, beautiful hair shorn off by the sea witch as payment for a chance to save their little sister.
* UnrequitedTragicMaiden: The titular mermaid, who ultimately chooses the prince's happiness over her own life and turns into sea foam. In some versions, she is rewarded for her sacrifice with becoming an air sprite.
* UpdatedRerelease: Twice.
* WantingIsBetterThanHaving: The Little Mermaid wishes to be a human and marry the prince. Because she gave up her mermaid life and became a human not being able to ever speak again and feel pain when she walked and danced and the possibility that she will die, it seems it would have been better for her to keep wanting instead of getting it.