Women are dancing. The same obese women are on display in the art gallery. Susan (Amy Adams), the gallery curator, drives home to her multi-million dollar estate overlooking the glimmering lights of Los Angeles. She has servants and security staff, which shows her great wealth. She gets a package from Edward Sheffield, her ex-husband and sees that it is a manuscript of his new book. It is dedicated to her and she reads that she inspired it. He will be in Los Angeles and wants to meet. The title is 'Nocturnal Animals'. Her head of security asks who should work for the weekend shift. She replies that she prefers to be alone; (hinting she plans to read the book.)
That night, she can't sleep and takes pills. The next morning, Hutton, her husband (Armie Hammer) joins her in the kitchen. She tells him that she wanted him to come to her show. He answers that he was working and that it was far away. She ignores his words and insists it was just a short show. He then claims he didn't get home until 1:00 AM and didn't want to wake her. She answers that she wasn't asleep until 4:00 AM (hinting that she knows he is lying). He asks about the manuscript so she says it's from Edward. Hutton comments that she hasn't talked to Edward in almost 20 years. She specifies 19 and explains that she called Edward but he hung up on her. Hutton says, "I didn't know Edward was a writer." She laughs at this, and says that Edward was writing when I met you; before the divorce. He changes the subject to tell Susan that he must go to New York that weekend to solidify a business deal. He adds that he hates art. She tells him she'll just start buying work from new L.A. artists so when people come over, they'll think they're ahead of the curve and not financially broke.
Susan begins to read the book which is dedicated to Susan. The first page is Tony Hastings (Jake Gyllenhaal) packing up his car for a road trip with his daughter.
That night, Susan and her husband throw a party in their home. A rather ostentatious friend, Alessia, (Andrea Riseborough) greets her and they have empty conversation with the friend wishing she could have been more supportive when Susan was depressed. Susan tells the friend about the manuscript dedicated to her and Alessia replies that she didn't know she had an ex-husband. Susan admits to feeling unhappy with life, even though she has so much and everything is going well (on a superficial level). The woman suggests she should have married a gay man like she did, and we see her husband, Carlos (Michael Sheen) chatting up a guest. Alessia points out that she will always be the only woman in his life and that's hard to come by with men.
The weekend comes and Susan is now alone. She continues to read the manuscript. We now see the story Tony is driving through Texas, late at night, without stopping with his wife Laura (Isla Fisher) and teenage daughter India (Ellie Bamber). They are having playful banter about their trip and the decision to drive 14 hours without stopping. India complains that there is no phone signal in that part of Texas. The road is empty except for two cars in both lanes ahead both are driving slowly and at the exact same speed. Tony honks his car to get one of them to move over so he can pass. One car does move over but immediately begins harassing Tony. His daughter flips off the driver. The car passes and its filled with three sleazy-looking men, glaring at Tony and his family. That car begins playing chicken with Tony's car, which he swerves to avoid. But eventually they hit his car and scream at him to pull over! Sensing danger, he ignores them. But the car continues to pursue them, finally slamming against their car and knocking them over to the side of the road.
Tony has no choice but to engage with the driver in the other car now. He comes over and hes a redneck (Aaron Taylor-Johnson) who comes off simultaneously charming and terrifying. He begins asking why Tony didn't pull over after Tony ran them off the road. Tony and his family respond that his car hit theirs but the redneck ignores them, continuing on about how they have to report accidents. The family knows something shady is going on. The car that was initially driving alongside the rednecks car zooms off, hinting that he was being harassed before Tony came along. Tony suggests calling the police. The redneck seems open to this but points out there's no signal which we already know is true. Tony says they'll drive to a town where they can call someone but the redneck points out Tony has a flat tire and he needs to get out of the car to change it. Tony doesn't believe him and so the redneck tells him he should try to drive away if he thinks hes lying. Tony does and he does, in fact, have a flat tire (although whether this happened from the collision or something malicious was done after the redneck came over isn't clear). He tells Tony he will change the flat tire for him and asks him to get out of the car to open the trunk. Tony is hesitant to leave his car because the man seems to be dangerous. But finally, he swallows his concern and gets out to open the trunk, removing their luggage so they can get the spare. Now he tells Tony to get his wife and daughter out of the car so he can change the tire. Tony tells him they're not leaving the car but the redneck is insistent the car should be empty if he jacks it up. A police cruiser drives by and Tony and his family try to signal it but it doesn't stop. The redneck laughs and says, There goes your police.
The other two rednecks get Tony's wife and daughter out of the car and begin harassing them. Tony tries to protect them but the redneck driver keeps preventing him. All the while, Tony tries to assuage the situation by being polite and non-confrontational. The redneck continues to taunt him. While he is being held up, the tire gets changed which sort of assuages Tony's fears for a second that maybe they're just immature and not dangerous. Tony orders his wife and daughter to get back in the car. The redneck driver asks how they're going to get into town to report the accident. Tony is confused and explains they'll each take their car. But the redneck deflects this idea, suggesting Tony could drive off and it'd be better if he went with their daughter and wife. The daughter and wife are against this, as is Tony, and they scream for Tony to get in the car. But before he can, the redneck and one of his friends hop inside and peel off in Tony's car. Tony watches his own car driven off with his wife and daughter inside.
One redneck is still left with Tony. He tells Tony to drive the other car, the one that the redneck was previously driving. Tony hopes that the plan is legit and that his wife and daughter aren't in danger. They drive down the empty stretch of highway until they get into an abandoned town. Tony is directed to turn down a dirt path. He passes his own car, empty and parked in the dirt. But the redneck tells him to keep driving. Tony tries to argue and the redneck responds, "Don't worry. They've never killed anyone.... yet". Tony demands to know where his wife and daughter are but the redneck just tells him to get out of the car. Tony is now alone, in the dark, in a clearing. Moments later, the redneck driver appears in Tony's car with the man who rode with Tony alongside him. Tony ducks behind a large boulder. The redneck is angry that his friend let Tony get away. His friend shouts out "Hey, mister. Your wife and kid want you". Tony stays put until they drive away. He then runs through the fields trying to find someone to help. He ducks under a barbed wire fence but cant get anyone to stop for him. He makes his way to a farmhouse where he asks to use the phone.
Back to Susan's home. She is shocked by the malevolent story and has to put it aside. She calls her husband in New York. He is walking affectionately with a female model who remains silent while he speaks to Susan. They get in an elevator and the bellhop asks which floor. Susan's husband says the 31st floor. This makes Susan suspicious as she says that's not their usual room. He responds by claiming he threw a fit when they didn't have their room available. They finally arrive at the floor and the bellhop turns to the woman and says, "31st floor, madam". Susan freezes, hearing this on the other end. She knows hes with another woman and freezes up. Finally, she speaks but only to say goodbye.
Susan struggles to sleep, as always, and then continues to read. In the story, a police officer named Bobby (Michael Shannon) comes by and asks Tony to tell him what happened. Tony explains the situation and Bobby points out that the men had no guns and asks why he let him drive off with his wife and daughter. Tony explains that they took the car and Bobby finds this incredulous. When Tony gets to the point where one of the rednecks says Your wife and kid want you, he asks why he didn't go to them. We know that Tony could tell the men were dangerous but in this small Texas town, everyone comes off hyper-masculine and prone to violence so Tony seems to be struggling justifying his non-confrontational response to the situation.
To find where Tony had last seen the men, he is brought back to the stretch of highway until he recognizes the barbed wire he had crawled through. He uses this to find the trail which leads them back to the area they had passed in the car. There is a small shack there and Tony is told no one has lived there for years. Tony is staying at a hotel in town while the search for his family is active and he is told to wait there until he hears back. Tony returns to the hotel, somber, obviously blaming himself for not being a more aggressive personality when his wife and daughter were threatened. The phone rings and Bobby tells him they've found fingerprints in the shack and it looks like it could be Ray Martin but he has no track record after being acquitted on a rape case years ago. He also tells Tony they found their wife and daughter. Bobby and Tony are driven to the area that Tony was in the night of the abduction and see the naked bodies of both his wife and daughter on a bench outside. He approaches, hoping they're asleep but they are both dead.
Susan stops reading, shaken up by the material. She calls her own daughter away at college; she has red hair just like India in the novel. The daughter is asleep (with her boyfriend next to her) and says its way too early where she is. Susan apologizes, once again up late, not sleeping. But we know she only called to check on her daughter after reading about the abduction of a teenage girl in Edwards novel.
Susan sends an email to Edward telling him she is reading his book and finds it devastating and brilliant. She suggests the two of them meet. She then has a flashback of running into Edward (also Jake Gyllenhaal, but looking younger than Tony) in New York even though they're both from Texas. Edward is in town because hes being considered for a scholarship to Columbia. He asks why shes not still at Yale and she says she graduated and is now in New York for grad school. Susan then asks Edward if he knows anyone in the city. When he says no, she asks him out to dinner.
Back in the story, Tony is called by Bobby, who tells him they found out his wife was killed with a hammer just a few hits and then she died with no suffering. But Tony is then told his daughter wasn't so lucky and she was suffocated to death. Bobby then adds that both were raped. Tony is sent a picture of who they suspect is the lead suspect, based on fingerprints. Tony observes the photo but doesn't seem to be able to identify him.
We flashback to the dinner in New York. Edward tells Susan he only hung around her brother to be around her because he had a big crush on her. She tells him Cooper had a big crush on him. He is surprised by this information and she tells Edward that he was her brothers first crush. Edward now feels bad he hasn't kept in touch with Cooper, now that he knows he liked him so much. Susan compliments him, that his reaction to finding out his best friend was in love with him wasn't fear or disgust but concern for his feelings. She wished her family was as open-minded but they disowned Cooper when he came out as gay, adding that she has nothing in common with them they're Republicans, conservative, racist, bigoted, narcissistic. Susan voices her detest of her family's arrogance and how her mom thinks shes better than others. Edward tells Susan that her mom and her both have the same sad eyes. She tells him she doesn't want to be compared to her mother and he asks why. She points out that they're completely different. Edward asks Susan why she abandoned her pursuit of an art career; she responds that she wasn't that good at it and is a realist who doesn't want to believe in success she will never have. He contradicts this, admiring her past work and saying shes perfect. She says shes not perfect but he suggests that shes much better than she accounts for and that she underestimates herself. She then asks him to go home with her, admitting that he was her first crush, too.
Susan begins reading again. Its been about a year with Tony depressed about his role in the abduction; he showers and shaves his beard off. Bobby calls to tells Tony that they caught two of the guys whose prints matched that night a guy named Turk who they shot dead and a guy named Lou who they're holding. They ask Bobby to come down to the station to identify Lou. Once there, hes asked if hes afraid of the men seeing his face but Tony isn't, now ready for justice. He looks at the five men and easily identifies Lou, who was the one who rode with Tony that night. Lou is taken away and charged. Now they have to find Ray Marcus, who is the most likely culprit. On the drive, Bobby tells Tony that he (Bobby) is dying of lung cancer. Tony points out that Bobby smokes all the time and Bobby shrugs it off, saying he only has a year left to live.
Tony and Bobby go to a small shack where Ray has taken residence Ray has had to fix the plumbing himself so at this moment, he is going to the bathroom outside. (Ray is played by Aaron Taylor-Johnson so he is definitely the redneck from that night). Bobby and Tony approach Ray as he ends a phone call and continues to use the toilet. They want to take him on suspicion of abducting and murdering Tony's wife and daughter. Ray asks if he can finish going to the bathroom first but Bobby tells him he cant take his eyes off him. So Ray wipes himself and then leaves with Bobby.
Tony drives Ray and Bobby to the station in his car, glancing at Ray in his mirror. Ray points out that Bobby never read him his rights but Bobby claims that he did and says that Tony will confirm this (hinting that Bobby doesn't do things by proper procedure). Ray denies ever having seen Tony before but Bobby points out that's probably because Tony shaved his beard. Tony glares at Ray, silently, much more confident than he was the night of the attacks. Bobby asks Ray questions and then tells him the conversation is being recorded.
Back in present day, Susan has a flashback with her mom (Laura Linney) in Texas. She forbids Susan from marrying Edward, suggesting she should wait until shes older. Susan reminds her mom that she had recommended another suitor for marrying and her mom admits that her real concern is that Edward is beneath her. She adds that Susan only likes Edward because hes romantic which isn't a bad thing but eventually Susan will regret being tied to him along with his sensitivity comes a man who lacks ambition and drive and will never achieve anything.
In their married life, Edward lets Susan read the novel hes working on. She is critical, citing that it isn't that good at the moment and saying he is writing about something too close to home and it lacks excitement. He gets defensive and angry with her. She explains she is merely being honest with him. Edward replies that he poured his heart into his work and he wants her to like her husbands work. She now denounces him writing the novel altogether, telling him its unrealistic to plan to work at a bookstore and bang out a novel every year. He tells her shes turning into her mother.
The next day in class, Susan picks up the pencil of another student who she immediately finds attractive played by Armie Hammer, who we know will eventually be her husband.
Susan goes to her art gallery, walking up several flights of stairs, pausing to look at a new piece of art hanging in the hallway titled REVENGE. Susan's assistant, Sage (Jena Malone), appears and preps her for the meeting. Sage tells Susan that she just got a Nanny Cam that she can watch on her phone because she doesn't trust her nanny. Susan observes the app, showing a baby in his crib and then a scary face jumps into frame and screams at her. Susan drops the phone and it shatters. She tries to explain to Sage there was someone on the phone but Sage replies, nonchalantly, that that person was her baby. Susan awkwardly apologizes for the phone but Sage tells her its okay because a new one comes out next week. In the board meeting, the women at the gallery are vapid including one who has had horrible plastic surgery, which she denies having. They discuss whether to fire a new employee who hasn't lived up to her potential, citing another young candidate who applied and would be more appealing. Susan interjects that they committed to teaching her and guiding her and shouldn't abandon her for someone else. It is pointed out that Susan took the opposite approach the last time it came up in discussion but Susan has now changed her mind (a metaphor for how she treated Edward).
In a flashback, we see Susan break up with Edward who begs her to stay faithful to him. He says that when you love someone, you focus on making it work, not on discarding them the first chance you get. He has tapped into something because she is pretty persistent that they divorce we know that she has met the man who will be her future husband and they'll marry shortly after the divorce.
Susan tells someone on her staff at home that nocturnal animal was a nickname Edward had given to her because she would always stay up late. He named the book after her and also dedicated it to her.
Back in the manuscript, Bobby visits Tony to tell him they have to let Ray go because they only had circumstantial evidence against him. Tony is devastated because he knows Ray is the one who killed his wife and daughter. Bobby says that a government official in his town wants to hire someone else as sheriff so he wants Bobby removed from his position, hence them not helping convict Ray to finish up his services. But Bobby is going to die and is willing to take the law into his own hands since he has nothing to lose he doesn't want his last case to be an unsolved murder.
Bobby and Tony find Ray in a diner and promptly arrest him with Bobby telling Ray that Lou snitched on him. Instead of the police station, they take him to the small shack where Tony's wife and daughter were raped. Lou arrives having been told that Ray snitched on him. Lou and Ray argue with each other, solidifying their involvement. Bobby goes to the bathroom to throw up, giving a gun to Tony and telling them not to move or Tony will shoot. When he returns, Lou tries to run so Bobby shoots him dead. Now that Ray realizes they aren't following the law, he runs out of the house. Bobby calmly tells Tony that he can catch up to Ray since he will need to make it all the way to the highway to hitch a ride from someone.
Tony finds Ray back at his home later that night, asleep. Ray wakes up, taken aback that Tony pursued him. He then begins taunting Tony, telling him he fucked his wife, adding he needs to be respected. When she told him no, he was mad and that's why he killed her. Tony points a gun at Ray, his hand shaking. Ray tells him hes holding a gun he doesn't know how to use. Tony screams at him, furious with an anger that was absent the night Ray and his buddies accosted his family. Tony cocks the gun but doesn't shoot. Unbeknownst to him, Ray grabs a fireplace poker. He eventually charges at Tony but he retaliates by shooting Ray once, then twice. Ray gets angry as he notices that hes bleeding to death. He strikes with the poker
Susan remembers sitting in the parking lot of a hospital with her future husband and through conversation, we learn that she feels guilty for having just had an abortion without telling the father, Edward. He assures her Edward will never find out but then we see Edward in the parking lot, glaring at Susan in the car. We now realize that Edwards meek nature caused him to lose both his wife and his daughter and he used that as a metaphor for a great novel, countering Susan's belief that he would never be a great writer.
Back in the manuscript, we see both Ray and Tony unconscious on the floor. But Tony comes to and it is revealed he was blinded with the poker by Ray, right before he died. Tony makes his way outside and stumbles down the stairs, bleeding from his eye. He falls on his gun and it goes off--
In present day, Susan receives a reply to her email to Edward, requesting they meet while he's in town. He simply says, "Tell me when and where."
Back to the manuscript, we learn that Tony has accidentally shot himself, right through the heart.
Susan shows up to a fancy restaurant all dressed up. She gets a table and waits for Edward. Time passes and he doesn't show up. More time passes. And it becomes clear that he has stood her up which is sweet revenge given that she made him feel worthless, she is now in a troubled marriage and unhappy with her life, and also now realizes what a great writer he was after all.