Nick Dunne (Ben Affleck) is stroking his wife Amy's (Rosamund Pike) hair, saying through a voiceover that he'd like to bash her head in and pick her brain apart to see what kind of secrets come spilling out.
July 5th, 2012 (The Morning Of) - Nick goes to a bar he co-owns with his sister Margo (Carrie Coon). He brings her a board game that she throws in with a pile of others. She takes out two glasses and pours Nick and herself some bourbon. It's the day of Nick and Amy's 5th anniversary. Nick seems distressed, not wanting to be home at all.
January 8th, 2005 - Nick and Amy first meet at a party in New York. He writes for a men's magazine and she writes personality quizzes for another. She makes a comment on his chin making him look untrustworthy. He puts two fingers on his chin to seem more trustworthy. They take a walk and pass through a bakery that is getting a sugar delivery. Sugar is floating around everywhere as Nick and Amy walk through it. Nick tells Amy he has to kiss her now. He wipes some sugar off her lips and kisses her. He later goes down on her.
In the present day, Nick returns home. He picks up his cat that's sitting outside on the front lawn. He enters his home and calls for Amy. No answer. He goes into the living room and sees a table flipped over and the glass surface is broken. Nick screams Amy's name, startling a neighbor.
Nick calls the police. Arriving at his home are Detective Rhonda Boney and Officer Jim Gilpin (Kim Dickens and Patrick Fugit). They inspect the place. Rhonda sees a smear of blood in the kitchen above the counter. In the living room, they see a wall with pictures of "Amazing Amy", a book series written by Amy's parents. Rhonda comments that she loves the books and is surprised to learn that Nick is married to Amazing Amy herself.
February 24th, 2007 - Nick and Amy go to a party held by her parents Rand and Marybeth (David Clennon and Lisa Banes). Rand asks Amy to go sit with bloggers and reporters to answer some questions. She does, and they get her with mundane questions such as if she hasn't been married yet. Nick comes in pretending to be a reporter, where he proposes to Amy by putting a ring inside a booklet.
Nick is brought into the police station for questioning about Amy's disappearance. Rhonda and Jim find it odd that he seems rather indifferent and passive when answering questions and the fact that he doesn't know if Amy has any close friends or her blood type. He goes to call Amy's parents. Her mother asks to speak to Rhonda. In the next room, Nick finds that his father Bill (Leonard Kelly-Young) is in there after the police found him wandering around town, having left the treatment clinic (he suffers from Alzheimer's). Nick drives him back to the clinic.
Nick stays at Margo's house while the police inspect his home. A pregnant neighbor, Noelle Hawthorne (Casey Wilson), who also claims to be Amy's best friend, comes by and asks about Amy. In the bedroom, Officer Jim finds an envelope in a clothing drawer, marked "Clue One" and notifies Rhonda.
July 5th, 2009 - Nick and Amy have been happily married for two years. They go to the library and have sex in a quiet area. They discovered they got each other the exact same expensive sheet set, in the same color with the same thread count, because of a previous conversation where Amy complained about sleeping in a terrible bed with terrible sheets..
When questioned about this "clue", Nick says it's something Amy made as part of a treasure hunt for their anniversary. The first clue leads him and Rhonda to his office, where a pair of red panties are found. The second clue there mentions a brown house, but Nick goes to his father's old home, which is painted blue. They find the third clue there, but Nick is unable to decipher it.
Amy's parents fly in from New York as a press conference is held to spread awareness of Amy's disappearance. Nick asks others for help, but he appears emotionless, and only makes himself look bad as he smiles next to the poster of Amy.
Nick and Amy's parents meet with Rhonda to determine some possible suspects. Rand names an ex-boyfriend of Amy's, Desi Collings, who apparently tried to commit suicide after Amy broke up with him, and a former classmate named Tommy O'Hara that allegedly sexually assaulted Amy, and so she pressed charges.
People go to the volunteer center to help find Amy. One person there is Desi Collings (Neil Patrick Harris). Nick tries to come off as friendly to others, but Jim doesn't buy it. Even Marybeth thinks he is acting like a "homecoming king." One woman takes a picture with Nick. He asks her to delete it, but she refuses. Consequently, this and other actions from Nick hit the media and TV personalities like Ellen Abbott (Missi Pyle) paint him as an unempathetic sociopath.
As Amy continued to document her married life in her diary, it is shown by their third year of marriage, both Nick and Amy were hit by the recession, and both of them lost their jobs. Amy tells Nick that she let her parents use her trust fund money, which is nearly a million dollars. Later on, Nick has started losing interest in the marriage and has begun overspending on electronics like video games and a new laptop. Amy thinks he is trying to make her look like a cold, bitchy wife. To make matters worse, Nick and Margo's mother Maureen (Cyd Strittmatter) was diagnosed with breast cancer, forcing Nick and Amy to move back to his hometown in Missouri. This led Amy to think that she was disposable and that Nick didn't need her anymore. Over time, he just kept using her for sex. They had an argument over having kids, leading Amy to hit Nick in the chest, and Nick grabbing Amy and throwing her against the staircase. He immediately looks shameful.
A few nights after Amy disappears, Nick gets a text from someone saying they are outside Margo's house. Nick opens the back door. A young woman, Andie Fitzgerald (Emily Ratajkowski), comes in and starts kissing Nick. He tells her to be quiet while Margo is sleeping. He makes sure that Andie hasn't said anything to anybody about her affair with Nick or that he has mentioned wanting to divorce Amy. They continue kissing and have sex.
Nick lets Andie slip out the door early in the morning, thinking Margo is still asleep. However, she is standing in the kitchen and angrily berates her brother for lying to her, knowing what would happen if the cops or media were to find out about this.
At night, there is a vigil for Amy. Nick stands alongside her parents, trying to seem more empathetic and hopeful to find Amy. Andie is in the crowd and calls him an asshole. Noelle walks by and calls out to Nick, asking him if he knew that Amy was six weeks pregnant. The reporters chase Nick all the way to the police car as they escort him out of there.
Margo presses Nick about the pregnancy bombshell. He says he did not know she was pregnant, but that he did want kids and Amy didn't.
Rhonda and Jim meet Nick back in his home and mention that someone wiped up a pool of blood in the kitchen. Nick also doubts that Amy knew Noelle, until Rhonda shows him photographs of the two of them, along with Noelle's kids. She even hands Nick a document of recent transactions from Amy's credit card, though Nick says he never bought any of those items. Additionally, Rhonda presses Nick about the fact that he upped Amy's life insurance policy earlier that year. Rhonda also gets a call after Amy's sample results come back, concluding that she was indeed pregnant.
While Nick tries to decipher the third clue of Amy's treasure hunt, Rhonda and Jim continue their investigation. They find a local dealer and show him a picture of Amy. He tells Rhonda that she came by and tried to buy a gun from him. They go back to Nick's father's home and go to the basement. In the furnace, they find what happens to be Amy's diary, burnt slightly from the outside. Nick, meanwhile, figures out the clue and is led to the wood shed outside Margo's home, where a large pile of electronics are stored, and a box in the middle of it all.
We go back to "the morning of", and we learn the truth - Amy is alive and she staged everything to lead up to her disappearance. She is seen driving away from Missouri with her arm bandaged up slightly. For a while, Amy has been writing false information in the diary to leave an implication of Nick being abusive towards her, as well as personal fears that he may kill her. She even planned to fake her pregnancy by befriending Noelle and making her think that Nick was hurting her. Amy drained her toilet and let Noelle drink enough fluids for her to use the bathroom, so Amy stole her urine and left a sample for the cops to find. On the day of their fifth anniversary, Amy let Nick go about his day while she set up a crime scene to make Nick look guilty. She has even planned ahead in case she needs to kill herself to completely frame Nick. To make sure she's not found out, she cuts her hair, dyes it, and makes herself look unkempt and disheveled, and she hides out at a small resort under the name Nancy, even hitting herself with a hammer in the face to sell it. She befriends a woman named Greta (Lola Kirke). Amy tells her how she came across Nick leaving the bar with Andie during a snowy night, wiping her lips before he kissed her the same way he kissed Amy when they first met (this part is true).
Nick brings the box inside and opens it to find Punch and Judy dolls, with the Judy doll missing a mallet. Together, he and Margo deduce that Amy has framed Nick for her disappearance.
Nick goes to New York to find Tanner Bolt (Tyler Perry), a lawyer that has been following Nick's story in the media. He agrees to help Nick prove his innocence. He gives Nick the contact information of Tommy O'Hara so that Nick can ask him questions.
Nick meets Tommy (Scoot McNairy) in a bar. Tommy says he met Amy at a party and had consensual sex with her, but she later framed him and made it look as though he raped her. Now he is a registered sex offender and has not been able to get a job. Nick later visits Desi after finding his address from a letter he wrote to Amy. After Nick asks Desi about his side of the story regarding his attempted suicide, Desi closes the door on him and walks back inside his house.
At the resort, Amy plays mini-golf with Greta and her friend Jeff (Boyd Holbrook). At one point, she jumps up and drops her fanny pack full of money. Greta and Jeff notice. The next day, they get Amy in her room and rob her. Now penniless, she calls someone from a payphone.
Tanner goes to Missouri to help Nick and Margo clear up Nick's image. Nick tells Tanner what he thinks has been going on with Amy, dropping clues that only he would really know. For instance, the reason he knew that the "brown house" in the treasure hunt clue was his dad's house was because they'd pretend that his dad was a spy called Mr. Brown. Nick also admits to the affair, which Tanner says he ought to tell the cops about so that it gives them one less reason to think Nick had a motivation to kill Amy.
Nick later books an interview on TV with Sharon Schieber (Sela Ward). Tanner coaches him to make him seem more likable by having Nick admit that he's been unfaithful and dishonest, which would earn him some possible points in the media.
On the day of the interview, Tanner keeps trying to get Nick to come off less smug and more genuinely upset by pelting him with gummy bears in his dressing room until Nick gets it right. At the same time, Desi finds Amy in a casino after he calls her. She never mentions getting her money stolen, but she continues to play up the abused wife angle. As they leave, and as Nick meets Sharon, a bombshell hits the news: Andie confesses to her affair with Nick at a press conference, in front of Amy's parents. Desi and Amy see the news at the casino while Sharon gets wind of it at the same time. Marybeth tells reporters that her and Rand's love for Nick ended then and there.
Desi takes Amy back to his home. Together, they watch Nick's interview with Sharon, which Nick is watching with Margo. Nick convincingly comes off as remorseful for the affair, but he insists that he did not kill his wife. Sharon lets him speak directly into the camera to say something to Amy. He says he loves her and drops mention of the woodshed (figuratively) before putting two fingers on his chin, knowing Amy would recognize that. Margo checks the internet and sees Nick is already getting more love.
Things take an unfortunate turn when Rhonda and other officers show up at Margo's home with a search warrant after getting an anonymous tip (but it was actually Amy) that there were loud noises coming from Margo's woodshed. They find all the electronics from the credit card bill. Both Nick and Margo are taken into custody. Rhonda reads to Nick the pages of Amy's diary, which is ended with "This man may truly kill me." Jim brings in the missing Judy mallet from the puppets, which gives Rhonda reason to implicate Nick and place him under arrest. Nick tries to give his argument, but Tanner shuts him up.
At Desi's home, Amy learns that Desi has security cameras installed nearly all over the place. While he's out at work, she soaks her nightgown in wine and crawls to the camera, making it look like she's just been raped as she fakes crying.
Nick and Margo are released on bond. The media continues to hound them on the way out, now that everyone is convinced Nick is a cold monster. Nick quietly whispers to himself, "Come home, Amy. I dare you."
Amy waits for Desi to come home. She gets a wine bottle and puts it in herself as she plans something. When Desi gets home, Amy seduces him and agrees to go with him to Greece. They go into the bedroom and start having sex. When Desi is caught off guard, Amy grabs a box cutter she was concealing and slashes his throat. She becomes drenched in his blood and leaves him to die.
Nearly a whole month after Amy's disappearance, Nick looks out his window to see that things seem quiet. In his driveway is Amy, still covered in blood. The reporters and neighbors are shocked and begin clamoring around Nick and Amy as she walks up to him. He whispers to her, "You fucking bitch", before she collapses in his arms.
At the hospital, Amy makes a story about how Desi kidnapped and raped her before she made her heroic escape. Rhonda asks her questions regarding the items in Margo's woodshed, but Amy ignores them in favor of telling her rape story, while also being heavily medicated on painkillers. The reporters follow her and Nick home, happy that she's alive and that Nick is now vindicated. However, Nick knows something is wrong. Amy lets him hop in the shower with her as she washes Desi's blood off her, and to make sure Nick's not wearing a wire. She all but outright states that she did frame Desi and murdered him to make her return seem heroic.
Nick meets with Tanner, Margo, and Rhonda (who now trusts Nick) about this revelation, though without sufficient evidence and with everybody on Amy's side, they cannot prove that she murdered Desi and framed Nick for her disappearance.
Nick and Amy make their first public appearance together at the volunteer center, posing as a happily reunited couple. They are even set to have an interview with Ellen Abbott. Amy gives Nick a gift, which is a pregnancy test. It's positive. Nick knows this is another ploy of hers to keep him with her, and he slams her head against the wall, calling her a cunt. She tells him she's the same cunt he fell in love with. Reluctantly, Nick joins Amy hand-in-hand for the interview. They break the news to Ellen, who is overjoyed and hugs Amy. Margo later finds out about the pregnancy and cries for her brother, knowing he is stuck with the real monster for another 18 years.
The film concludes with Nick stroking Amy's hair again, wondering to himself just what she's thinking.
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