->A butterfly flaps its wings in Brazil and a tornado brews in Texas. A simple choice: Today or Tomorrow? Conceived a day earlier, the Boy Who Lived was never born. He wasn't even a glimmer in his parents' eyes.

->But she was; Harriet Lily Potter... Harry; the girl that grew up in a cupboard; the girl with safety-pinned knickers; the girl that was never wanted by the only family she had left; the girl that would give anything for the slightest bit of love.

->With a lightning bolt scar, her mother's face, and her father's messy hair, Harriet Potter has always been far less than welcome in the Dursley household. Ten years old, unloved, and uncared for, Harry has already seen more hardship than most will see in their entire lives. In fact, her life can't get much worse. Yet on July thirtieth, a strange letter is pushed through the Dursley's mail slot, turning her miserable world upside down. Discovering her magical heritage, Harry finally finds a place to belong and, after a chance meeting in a train station, she just might have found someone to love her.

->What happens when the shoes of a hero are filled by the feet of a heroine? How does the world change? How do relationships change? How important can one person possibly be?

->Follow Harry down the familiar path. Follow her as she steps off it. Walk with her as she creates ripples of flux that grow and twist into massive tsunamis, changing the course of history as we know it... for better or for worse.

[[http://www.fanfiction.net/s/6008512/1/A_Butterfly_Effect A Butterfly Effect]] by [[http://www.fanfiction.net/u/468338/SlyGoddess SlyGoddess]], is a GenderFlip WhatIf ''Literature/HarryPotter'' fanfiction epic that stars Harriet Lily Potter, the Girl-Who-Lived, and fleshes out Creator/JKRowling's universe while skillfully avoiding many of the common fanfiction pitfalls.

Currently a DeadFic.

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!!This fic provides examples of:
* {{Backstory}}: Albus Dumbledore and Gellert Grindelwald.
* CannotDream: Harriet can't let herself dream else she [[spoiler:has a murdermare freakout that makes her lose control of her mind to Voldemort's soul fragment, turning her into the scary-as-all-hell psychopathic 'Harrymort' who commits murder like it's her day job.]]
* TheChessmaster: Many characters. On a literal level, Ron and Dumbledore; Harriet is also quite good, though still not quite as good as Ron, even at her best. Yes, this often leads to a GambitPileup, for better or worse.
* ClosetKey: Marin has a reputation for this. [[spoiler: Works on Harriet.]]
* DarkerAndEdgier: Harry suffers from some rather serious abuse early on. It also contains (sometimes graphic) violence like decapitation, torture, and rape.
* DoomedProtagonist:
** [[spoiler:Harriet]] is clearly going to die at the end of the series and yet somehow, there is still supposed to be a happy ending.
** Considering how the canon story ended, it isn't that hard to imagine ways for [[spoiler: Harriet to survive just like Harry did.]]
* EquivalentExchange: Incorporates a dark, 'Fullmetal' element to the magic of Alchemy.
* EvilCounterpart: Though they're never actually shown to encounter each other, Herpo the Foul is arguably this to Nicholas Flamel-two impossibly old, quasi-immortal wizards who have a massive influence on history under various pseudonyms, teaching powerful figures of legend the craft of magic.
* FromBadToWorse: There are only a handful of chapters where none of the main characters are seriously injured, [[OnlyMostlyDead nearly killed]], tortured, maimed, sexually assaulted, or ''worse.'' And that's just the characters. [[spoiler: Harry gets possessed by her horcrux on multiple occassions, one of which causes the deaths of 30 people and the destruction of the Hogwarts Express.]]
* {{Flashback}}: So many.
* {{Gayngst}}: Plenty.
* GlowingEyesOfDoom: [[spoiler:Ginny's]] first impression when she sees [[spoiler:Harriet's magically augmented]] eyes, though she quickly sees past the FreakinessShame.
* HiddenDepths: His role shrouded in mystery, Nicholas Flamel is made relevant to the underlying original plot.
* IJustWantToBeNormal: Harriet detests the dark magic she is privy to and hates herself for using it, despite these instances often being out of her control.
* IKnowYouAreInThereSomewhereFight: Happens on several occasions.
* LipstickLesbian: Both Harry and Ginny fit this role, with Ginny being dominant and Harry being sub (though they do "switch" sometimes, depending on the circumstances). Emotionally (and in terms of the overall relationship), Harry and Ginny normally avoid any sort of dominant and submissive roles, though Ginny's brash, stubborn, and headstrong personality do come into play.
* LongingLook: Nowhere near as prominent in this fic as they are in a certain sparkly vampire novel, but they're still noticeable. Usually precedes major outpouring of feels.
* LoveDodecahedron: [[spoiler: Harry, Ginny, Ron, Hermione, Luna, Draco, Pansy, Michael Corner, OC named Marin]]... and that's all by the end of 3rd year. This gets largely resolved and simplified by the end of 3rd Year, though whether or not anything will complicate it again remains to be seen.
* NecessarilyEvil:
** [[spoiler:Gellert Grindelwald]]... who can be surprisingly endearing and yet totally despicable at the same time.
** This is also how Dumbledore describes the Dursleys being forced to [[spoiler: experience Harry's "death" from her perspective, to show them the other side of their horrific abuse]].
* NobleBigot: Draco Malfoy is still a jerk, but he's a helpful jerk that tends to do the right thing in the hopes that he will someday get into Harriet's pants.
* NonSequiturThud: [[spoiler:"I... I don't like peas." - Who doesn't love Luna?]]
* OriginalFlavor: [[SubvertedTrope Subverted.]] It feels like this...at first. Then the author puts the characters through the wringer. Also, some of the characters are far more sexual than in canon.
* RoundCharacter: Canon Ginny is somewhat flat in terms of background and personality, whereas 'A Butterfly Effect' Ginny is detailed. Dozens of characters also get this treatment, from Dumbledore to Lavender Brown.
* SerialEscalation: The power levels of some characters. Think Harry is powerful? Nah, she's [[spoiler: still no match for Dumbledore. Voldemort is more powerful still. Of course, Herpo the Foul makes all of them look like toddlers.]] Thankfully, though, it's presented as foreshadowing, exposition, or mythology-level storytelling instead of a cliche drama-producing tool.
* SlidingScaleOfAlternateHistoryPlausibility: Roughly Type 2.
* SmellsSexy: Harriet and Ron really like the smell of strawberry (Ginny) and toffee apple (Hermione), respectively. To a lesser degree, Hermione and Harriet enjoy the smell of grass (Ron) whereas Ginny and Luna enjoy the smell of pine (Harriet).
* SugarAndIcePersonality: [[spoiler: Pansy Parkinson]] is the end all be all of AlphaBitch {{Tsundere}}s. She has the rather miraculous ability to oscillate her behavior patterns between those of a full-blown {{Ice Queen}} and those of a consummate PrincessClassic.
* ThePowerOfLove: Considerably ''more'' powerful and significant than in canon.
* TransparentCloset: [[spoiler:Ginny's]] attraction to [[spoiler:Harriet]] seems to be headed this way.
* UnresolvedSexualTension: ''All'' of the main characters at one point or another.
* VillainTeleportation: Obviously, wizards in HP can apparate, but [[spoiler:Grindelwald, thanks to his fourth Hallow, can portkey anywhere, passing seamlessly through any and all magical protections. The portkey is powered by thought. Almost feels like he is a everywhere, always watching.]]
* WhatTheHellHero: Ginny has quite a few moments, only some of which are called out. Likewise, Harry [[spoiler:uses Legilimency to force Pansy to view Quirell raping Lavender every time she closes her eyes.]] Why? Because Pansy was shooting spitballs at her
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