On the hot July morning of his fifth wedding anniversary Nick Dunne arrives at the bar he co-owns with his twin sister, Go, in their hometown of Carthage, Missouri. After being laid off two years ago from their magazine jobs in the midst of the Great Recession, Nick and his wife, Amy Elliott Dunne, moved from Brooklyn to Carthage to help care for Nick’s ailing mother, Maureen, who has since passed away. From Nick and Go’s conversation at the bar, it becomes clear that Nick and Amy’s marriage is stale and uninteresting. When Nick receives a call telling him that his cat has gotten out, Nick drives to his and Amy’s large home in the suburb of North Carthage to find the front door standing wide open, and his wife “gone.”
As the investigation begins, Nick’s present alternates with diary entries written by Amy over the course of the last seven years. As Nick cooperates with investigators, including lead detectives Rhonda Boney and Jim Gilpin, answering their questions about his marriage with self-admitted lies, Amy recounts the heady early days of her and Nick’s whirlwind romance. In the present, Nick attempts to solve a treasure hunt Amy has left behind for him—their yearly tradition—while in the past, Amy recounts falling in love with Nick and marrying him, promising that she’d never be a traditional nagging wife and would never treat him like a “dancing monkey.”
As Nick solves more and more of Amy’s clues, he remains stoically unconcerned about his wife’s well-being, suggesting his guilt to the skeptical police; it’s eventually revealed that he has a twenty-three-year-old mistress named Andie, one of his students at the local community college, and has been seeing her for over a year. As Nick halfheartedly tries to fend off Andie’s desperate attempts to contact him, he struggles with the police’s increasing skepticism. They present him with credit card statements indicating over two hundred thousand dollars’ worth of debt, explain that blood was found all over the Dunnes’ kitchen, discovered that on Valentine’s Day of this year Amy went to a local abandoned mall known for housing junkies and homeless to try to buy a gun—and what’s worse, the Dunnes’ neighbor Noelle Hawthorne reveals publicly that Amy was pregnant, something that shocks Nick, as she always seemed uninterested in children. Amy’s diary entries reflect all of this, stating that she began feeling unsafe around Nick after he started “us[ing]” her for sex, and yet shoved her when she came to him expressing her desire to have a child. Amy’s diary entries end on a somber note—“this man might kill me”—as Nick, in the face of mounting evidence against him, contacts Tanner Bolt, a famous defense lawyer known for acquitting guilty husbands. After briefly flying to New York to secure Tanner’s aid, Nick figures out the last of Amy’s confusing, rhyming treasure hunt clues on the plane home. Horrified, he runs over to Go’s house to visit the woodshed at the back of her property referenced in Amy’s clue—he swings open the doors to find expensive luxury merchandise such as electronics, golf clubs, and clothing, plus a cache of violent porn. On top of all the credit-card purchases sits a shining present wrapped in silver paper.
Amy takes over the narration—she says she is “so much happier” now that she’s “dead.” Amy has spent nearly an entire year familiarizing herself with police procedure and laying the groundwork for her own “disappearance.” She has orchestrated the entire thing top to bottom in hopes of framing Nick for her murder and sending him to prison as revenge for his affair with Andie. Amy feels that Nick has, over the course of their marriage, slowly “killed [her] soul,” and that this is a crime worthy of extreme punishment. Amy reveals that the allegations of abuse and rape she made against Nick within the pages of her falsely constructed, hurriedly written diary were false—what’s more, she was never pregnant, but used the pregnant Noelle’s urine sample to fake a pregnancy on her own medical record. Amy is satisfied that she has left enough incriminating evidence to indict Nick—but as she makes her way into the Ozarks to go into hiding, she’s prepared to call and leave anonymous tips to push the investigation along in the right direction if need be. She plans to kill herself on the Mississippi in a few months’ time and make sure her body washes up as the final piece of evidence to secure the death penalty for Nick—the state of Missouri doles out capital punishment.
Back in Carthage, Nick tells Go that Amy is framing him, and shows her the contents of the woodshed as proof. Together, they bring the present inside and open it—it contains a pair of antique Punch and Judy puppets. The Judy puppet is missing her handle and has a baby puppet on a string tied to her belly. As Go researches the significance of Punch and Judy puppets, she learns that the violent puppet routine often features Punch killing Judy and their baby. Meanwhile, Nick breaks things off with Andie, but she is angry, and Nick is worried the news of their affair will soon get out. Amy, meanwhile, sets up shop at an extended-stay motel in the Ozarks. She meets her neighbors, a shady fisherman named Jeff and a young woman with a split lip named Greta. Amy spends all her free time watching coverage of her own disappearance on the news, delighting as newscasters cast doubt on Nick’s innocence and revere Amy as a beautiful, brilliant, devoted wife. In Carthage, Nick, Tanner, and Go figure out that at each stop on the “treasure hunt,” Amy has left an incriminating piece of evidence. The one place that hasn’t turned up any evidence is Nick’s father’s house, which stands unoccupied—Bill is in a nearby nursing home, suffering with Alzheimer’s.
Nick begins calling up people from Amy’s past—people she’d told him had wronged her in various ways—and attempts to get to the truth. A girl named Hilary Handy, accused of stalking Amy in high school, tells Nick that Amy orchestrated the entire thing after Hilary started flirting with a boy Amy liked; a man named Tommy O’Hara, charged with raping Amy, reveals that after Amy found out he was seeing someone on the side, she visited his apartment, tied restraints to his bed, ordered him to have rough sex with her, and later presented the police with evidence that she’d been raped. Nick begins to truly feel scared for his own life. He goes to a bar downtown to drink, and a cute female reporter sidles up to him and asks if she can tape some questions. Nick agrees to the interview—and, knowing that Amy is out there listening, decides to use the opportunity to tell his wife exactly what she wants to hear.
In the Ozarks, Amy accidentally provides Jeff and Greta with a glimpse of the money pouch she keeps around her waist under her clothes at all times. She begins to get paranoid, and considers leaving. Before checking out of the motel, she goes to the library to check up on the latest news—she sees an interview with Nick has gone viral. In the interview, Nick admits to having let Amy down—he speaks about his wife in fawning, adoring terms, and begs for Amy’s safe return. Amy is charmed, and unsure of whether she should carry out her original plan. Amy returns to her cabin to clear out—Jeff and Greta storm in, beat her up, and rob her, taking eight thousand dollars and leaving her with just a few quarters. Back in Carthage, Nick rides the high of his skyrocketing public image and prepares to do an even bigger TV interview with the famous Sharon Schieber. Meanwhile, Amy decides to call up Desi Collings, a former boyfriend who lives in St. Louis. Amy and Desi dated in boarding school—and Amy spread false rumors that after their breakup Desi began stalking her and even tried to kill himself in her dorm room. Amy meets up with Desi at a casino on the Mississippi—he has pined for her all these years, and offers to hide her away at his luxurious lake house. As she and Desi walk out of the casino together, Amy passes by a TV—and sees Andie giving a press conference, revealing the truth of her affair with Nick.
Reeling from the fact that the press has gotten to Andie, Nick gives another simpering interview in which he desperately begs for his wife’s safe return. The team returns to Carthage feeling triumphant, excited for the interview to air the following evening—but when they get back to Go’s house they’re confronted with Boney, who has obtained a warrant to search Go’s woodshed thanks to an anonymous tip. After searching the woodshed, Boney and Gilpin take Nick and Tanner down to the station for questioning—they set Amy’s fake diary down on the table in front of Nick, and point out that the Judy puppet is missing her handle. The detectives posit that the handle is big enough to have been used as a murder weapon. Nick knows he is in deep trouble.
Desi and Amy arrive at the lake house, and as Desi gives Amy the grand tour, she gets the sense that he has been decorating and grooming the place for years to her liking, anticipating her return. That evening they watch the Sharon Schieber interview together, and Amy is completely taken in by Nick’s heartfelt answers. She decides that she needs to find a way home to him. Back in Carthage, Nick waits around in his and Amy’s house for days, knowing that the cops will come to arrest him in a matter of time. He begins thinking horrible thoughts about killing Amy. After several days, the cops turn up the handle—which has trace amounts of Amy’s blood on it—and officially arrest Nick. Amy, meanwhile, realizes that she is trapped at Desi’s—he is restricting her food intake to make her lose weight, and reminds her often that if she ever flees the house he’ll go to the police out of “concern.” Amy begins concocting a plan to escape. One evening, she allows Desi to finally have sex with her, and asks him to make it rough. After their lovemaking, she fixes him a spiked martini—as he falls asleep, she gets to work.
Nick is out on bond awaiting trial forty days after Amy’s disappearance. One afternoon, the doorbell rings—a disheveled Amy, covered in blood, is on the doorstep. She throws herself into Nick’s arms as the cameras flash, and Nick embraces her—but whispers in her ear the words “you fucking bitch” before pulling her inside. In the privacy of their home, Amy puts on a crazed smile and tells Nick the elaborate story of how, forty days ago, Desi showed up at the house, clubbed her with the Punch and Judy handle she’d been trying to fix in time for the anniversary, and kidnapped her. She claims she has been living as Desi’s prisoner for over a month. Nick doesn’t buy Amy’s lies.
The medical examiners confirm that Amy has been raped, and she tells them she slit Desi’s throat to escape him. The police head for St. Louis to find Desi’s body, and Boney and Gilpin question Amy about the details of her kidnapping. Boney tries to poke some holes in Amy’s account, but Amy has prepared every detail perfectly. Back at home, Amy strips Nick to make sure he isn’t wearing a wire, then drags him into the shower, where she tells him the whole truth and asks him to admit how “brilliant” she is. Nick tells her that he doesn’t want to stay under the same roof under her anymore—but Amy assures Nick she can still make “very bad things” happen to him if he leaves her. That night, Nick calls Tanner to tell him what’s happening—but Amy listens in, and comes downstairs to interrupt the call. As Nick begs Amy to let him go, the two get into a horrible physical fight. Nick nearly chokes Amy to death before he realizes that without her, he doesn’t know who he would be anymore—Nick releases her, sobbing.
As the days go by, Amy realizes she needs to put another “precaution” in place to keep Nick under her thumb. As Amy secures a book deal of her own, she is grateful for the chance to at last tell her own story the way she wants to. Amy is unaware, though, that behind her back, Nick is surreptitiously meeting with Go and Boney to try and come up with a case against Amy. Boney’s hands are tied, but she believes it is only a matter of time before Amy cracks and gives them something they can use. Nick’s father dies that autumn, and he finds himself, to his great surprise, turning to his wife for support—as he realizes that he’s playing Amy’s game and falling into her trap, he becomes desperate to pull himself out, and begins writing a memoir of his own. Amy knows what Nick’s doing, but is unable to get into his laptop to read his work. Five months after Amy’s return, Nick has at last finished the manuscript. He packs a bag, presents Amy with the book, and tells her he’s leaving. Amy presents Nick, in return, with a positive pregnancy test. Nick realizes that Amy has used a sperm sample of his that was kept at a local fertility clinic for years after their failed attempts to have a child long ago to impregnate herself. Spurred by the trauma of losing his father and determined to be a good father to his own child, Nick at last relents and admits he has been “outplayed.” Nick destroys the manuscript and accepts that he and Amy are one another’s perfect match—without Amy, his “forever antagonist,” he would not be the man he is.
Amy, determined to have the last word, writes one final missive. She has been home for nearly a year, and her baby is due tomorrow—the same day as her and Nick’s sixth wedding anniversary. Amy writes that earlier this morning, Nick was stroking her hair. She asked him why he was always so good to her, and he replied that he feels sorry for her—because every morning, she has to wake up and be herself. Amy is upset and confused, and cannot stop thinking about Nick’s words.