Amy Elliot-Dunne is the main antagonist of the 2012 best-selling novel and 2014 David Fincher film, Gone Girl, both written by Gillian Flynn.
In the film, she was portrayed by the British actress, Rosamund Pike, who is also known for her roles as Miranda Frost in Die Another Day (2002), Dr. Samantha Grimm in Doom (2005) and Samantha "Sam" Chamberlain in The World's End. She was also nominated for the BAFTA, Golden Globe, Screen Actors Guild and Academy Award for Best Actress in 2015 for her performance as Amy, but lost the awards to Julianne Moore for her performance in Still Alice.
Amy believes that she should never have been born. She came into the world after a series of stillbirths and miscarriages, and all these girls were named Hope, and Amy was always haunted by these girls who were treated as angels because they died as babies. As a child, Amy was the inspiration for her parents to create Amazing Amy, a series of popular children's books. The character of Amazing Amy earned tremendous spite from the real-life Amy, who constantly lived under the shadow of the seemingly flawless version of herself that her parents created.
Later in life, she meets Nick Dunne at a party, who is a writer like she is. They quickly hit it off and begin a relationship, becoming married two years later, which greatly pleases Amy, as it is the only thing that Amy can share with her literary counterpart (Amazing Amy gets married in the final book of the series).
Their marriage is going great until the 2008 recession, causing them both to lose their jobs. On top of that, her parents request a large sum of money that nearly drains Amy's trust fund and thus her and Nick's finances, putting their marriage on the rocks. At the height of all of this, Nick's mother is diagnosed with Stage 4 breast cancer, forcing Nick and Amy to move from their townhouse in Manhattan, New York to a home outside of St. Louis, Missouri, where Nick gets a job as a creative writing teacher while he cares for his ailing mother.
After the death of Nick's mother, Nick and Amy's relationship continues to decline, Nick only seeming to give Amy attention when they are having sex. After purchasing a bar for Nick (which he runs with his sister, Margo), Amy later finds him with Andie, a student of his. She sees him wipe the snow off Andie's bottom lip as they're standing outside The Bar, and they kiss, which Amy realizes parallels the night her and Nick first met when he wiped powdered sugar off her lip in a alley before they kissed. After gaining the knowledge that she is being cheated on, she puts her grand scheme into motion.
She begins by befriending a frequently-pregnant neighbor, Noelle, whom Amy deems "the local idiot." She later begins to purchase many expensive electronics with credit cards she put in Nick's name to create credit card debt, has Nick increase her life insurance for her, buys a cheap getaway car, writes bogus diary entries that make her seem sweet and good-hearted while exaggerating and fabricating Nick's abuse towards her and her fears of him murdering her, and fakes pregnancy by stealing Noelle's urine.
It's unknown whether or not Nick actually shoved Amy against a flight of stairs as she said in her diary. On one hand, most (but not all) things in the diary are made up, and Amy was trying to make Nick out to be the bad guy. But we also know Nick is capable of hurting Amy, since he shoved her against a wall and almost choked her to death after her return. He tells the police that he "never touched her", but Nick is an unreliable narrator and even tells the reader that he had told the police lies.
On the night before Nick and Amy's anniversary (where Nick was going to ask Amy for a divorce), she plans a scavenger hunt with objects connected to his betrayal: the diary (which she partially burns in the furnace of Nick's father's home), a pair of Andie's panties left in his office at his job at the community college, and the electronics with a box containing a Punch and Judy puppet set. The next morning, she sets up her faked murder, rigging the house to imply a struggle, killing, and quick cover-up by knocking over picture frames on a rickety shelf and putting them back, drawing her own blood that she spills on the kitchen floor and messily mopping it up on purpose, and putting her blood on a blunt object which she burns in their fireplace.
By the time Amy leaves, Nick discovers and reports her disappearance. The neighbors (namely Noelle) and authorities soon suspect Nick in Amy's quickly apparent murder, causing him to be crucified on national TV and ostracized by his family and community (which is heightened by the fact that Amy was supposedly pregnant when "murdered").
Meanwhile, Amy drastically changes her appearance and starts a new life as "Nancy," drawing thousands of dollars in cash to support herself. She later meets her new neighbors, Greta and Jeff, who Amy isn't sure about whether or not they know who she is. One night, Greta and Nick catch Amy with her money, prompting them to break into her house and violently rob her, leaving her penniless.
She then comes into the re-acquaintance of Desi Collings, a wealthy former boyfriend of hers who has grown obsessed with her. Knowing she staged her death because of Nick (whom she says was abusive towards her), he takes her into his lavish lake house nonetheless and promises to keep her safe and be a good lover.
One night, Nick goes on national television with the help of his sister and his defense attorney, where he admits to cheating on Amy with Andie, but denies murdering her. Amy and Desi both watch as Nick gives a heartfelt apology (as well as some subtle inside jabs relating to her scavenger hunt) about his betrayal. Nick gives a heartfelt plea to Amy, telling her that he will find her and that he loves her, and he touches his chin, a personal sign between him and Amy that's used to tell the other that they're telling the absolute truth.
With her love for Nick now renewed, she uses Desi's security camera system and a wine bottle to convincingly set herself up as a violently-abused rape victim. That night, Amy lures Desi in for sex, where she slashes his neck with a box cutter and covers herself in his blood. The next morning, Amy arrives to Nick's home in Desi's car, covered in blood and looking frightened, all in front of the numerous news outlets parked on Nick's street. She stumbles out of the car, and up to Nick, tenderly touching his face and collapsing in his arms. Desi is blamed for Amy's kidnapping, and everyone (minus Nick, Boney, a female detective that investigated Nick since the beginning, Nick's sister Margo and Desi Collings' mother) is more than willing to believe her story, despite the glaring holes within.
After washing Desi's blood off her, Amy and Nick get into a fight which escalates to be physical abuse when Nick slams Amy against a wall and almost chokes her to death. He only stops when he realizes one thing: Who would he be if he killed Amy? He says it's not the morally right answer, but the reflective one: he needs Amy, and Amy needs him, and that he was at his best when he loved her. In the movie, Amy says, "I'm the cunt you married. The only time you liked yourself was when you were trying to be someone this cunt might like. I'm not a quitter, I'm that cunt. I killed for you; who else can say that? You think you'd be happy with a nice Midwestern girl? No way, baby! I'm it." They're toxic for each other, but they're also perfect for each other in a horrible way.
Nick and Amy are back in the same house again, and they're taking precautions around each other, even though they have different ideas of what's going on. Nick begins by walking on eggshells, not sleeping in the same bed as Amy, trying his best to not upset her, but things change a bit inside his own mind. One morning he goes downstairs and Amy silently offers him a cup of coffee, and he accepts, and he realizes that it's almost like how it used to be and is unnerved by the fact that he's not very afraid of her. Amy thinks that Nick loves her again, though she knows that he needs time to adjust. She's just happy that he's back with her. Nick has been writing up an expose detailing his side of the story, determined to expose Amy. He speculates that people will take sides, he even muses the idea of opposing t-shirts. Amy hears his clacking away on his keyboard, and finds his manuscript. She decides to take a "final precaution" to make sure he stays with her.
Nick plans to leave Amy, to show her the manuscript and walk out the door, and when he shows it to her, she says she has her own surprise for him. He watches her take a pregnancy test, and it's positive. Amy impregnated herself with Nick's frozen sperm that he thought Amy had discarded, because he saw the notice from the fertility clinic in the trash. They go to the clinic, and it's verified: Amy is pregnant, and it's a boy. He asks what would happen if he left her with his baby, and she says that would be "very sad".
All in all, Nick stays with Amy. He could leave or get a divorce, but he won't for three reasons. One: it would appear as if he has abandoned her once again in the media eye, losing the respect he had just gained back. Two: he doesn't want to leave Amy alone with his son. He shudders to think what lies she would whisper into his son's ear when he's not around, and doesn't want the only time he can see him to be in a small room with a supervisor nearby. Nick, after all, did want a child, and he vows to be a good father, a better father than he had. Three: he doesn't know what he would be without her. He remarks that the best man he's ever been was when he was the man that he thought Amy would like. He says he can't imagine life without Amy, that she is his "forever antagonist", and that they are "one long, frightening climax".
The final chapter of the book is from Amy's perspective the day before the baby is due, and she says that Nick has been the poster child for a man taking care of his pregnant wife, getting her pickles, rubbing her feet, etc. But she's bothered by one thing, one thing she can't stop thinking about. The other day she asked Nick why he was being so awfully nice to her, and he responded that it was because he felt sorry for her. When she asked why, he says, "Because you have to wake up every morning and be you." She concludes their story by saying that she just wanted the last word, and that she felt like she deserved to have it.