A young woman named Andrea “Andy” Oliver works in her hometown in Georgia, after several years struggling to make a living in New York City. Though she initially returned to Georgia to take care of her mother, Laura, during her treatment for breast cancer, Andy has remained at home long after Laura’s recovery, settling into a dull routine. 

Andy’s ordinary life is quickly disrupted while celebrating her 31st birthday with her mother in a diner. A young man named Jonah Helsinger enters the diner, shoots two patrons, and almost kills Andy before Laura intervenes. To Andy’s surprise, Laura, a professional speech pathologist with no combat training, handles the shocking circumstances with precision and expertise. When Jonah stabs Laura in the hand with a knife, she uses the knife, still embedded in her hand, to stab him in the neck. Rather than disarming the injured young man, Laura proceeds to slash the knife across his throat, killing him.  

Later, while Laura is in the hospital, Andy resists questioning from police detectives with the help of her father, Gordon, a lawyer who is divorced from Laura. A video of the incident, which shows Laura’s calm demeanor and skillful though violent actions, has been circulating on the news, and Andy realizes that her mother might face serious legal consequences. After leaving the operating room, Laura dismisses the police, insists on returning home immediately, and coldly instructs a shocked Andy to move out of the house by the end of the day. Before leaving the hospital, Andy speaks to a friendly young man named Mike, who asks her about Laura.  

That night, Andy is packing to spend the night at Gordon’s house when she sees an unfamiliar man in a hooded jacket, whom she nicknames Hoodie, sneaking into Laura’s home. Following him, she hears the man reference someone named Paula Kunde in conversation with Laura before he begins torturing her, making unclear demands. Andy walks up behind the man and smacks him with a frying pan, killing him. Before the police arrive, Laura urges Andy to take the keys to the man’s car and drive up north to a storage unit where she can exchange it for another car. Further, she instructs Andy not to contact her or Gordon until they have reached out to her.  

Driving up north, Andy makes her way to the storage facility, where she finds an unused car, hundreds of thousands of dollars in cash, and a box containing photos of a much younger Laura, who has been brutally assaulted. Speculating that her mother must have hidden a criminal past, she drives to a motel and gets a drink in a bar across the street, where she is shocked to find Mike, who claims that their meeting is just a coincidence. Mike flirts with her and they kiss in the parking lot before separating. Recognizing a rabbit-foot charm in his car, Andy realizes that Mike’s car was parked near Laura’s house on the night she was attacked by Hoodie, which suggests to Andy that Mike is involved in the shadowy group that attacked Laura. The next morning, she drives away, deciding to find Paula Kunde after looking her up online and discovering that she is a professor at the University of Texas-Austin.  

In Austin, she meets Paula, who responds to her with hostility and acknowledges that she knew Laura in the past. Additionally, Paula tells Andy that she spent 20 years in prison for a crime that Laura was also involved in, suggesting that Laura was able to escape justice. Suddenly, Paula brandishes a shotgun at Andy, but then lets her go. Andy runs out of the apartment and is surprised to discover Mike outside. She kicks him in the groin and takes his keys, driving off in his car to find a person named Clara Bellamy, another former acquaintance of Laura.  

Andy’s journey in is interwoven with chapters describing events in the past that, at first, have an unclear relationship to Andy and Laura’s story in the present. In 1986, a young woman named Jane Queller assists her brother, Andrew, and her boyfriend, Nick, in carrying out a secret plan to humiliate her father, Martin Queller, CEO of QuellCorp, at an economics conference in Oslo. They help an American woman named Laura Juneau sneak into the conference so that she can debate Martin and throw packs of red dye at him, symbolizing the blood that is on his hands due to QuellCorp’s corrupt mismanagement of its mental health facilities. However, someone in the group gives Laura a gun instead of dye-packs, and she kills Martin and herself. Later, when they return to California, Jane, Andrew, and Nick are interviewed by the FBI, who correctly suspect that they are involved in the terrorist group Army of the Changing World, which has claimed responsibility for the shooting.  

After a shootout with the police at their hideout, Jane, Andrew, and Nick escape alongside a fanatical group member named Paula to a “safe house” owned by Clara Bellamy and her husband, Edwin. There, the manipulative and abusive Nick, who leads the group, forces Jane to decide between caring for Andrew, who is dying of AIDS, or following the rest of the group as they plan bombings in New York and Chicago. When she chooses to help Andrew, Nick brutally beats her in a failed attempt to induce an abortion, revealing that he knows that she is pregnant. Later, after driving Andrew to an emergency room to die peacefully, Jane confronts her older brother, Jasper, who has signed off on the illegal and immoral policies of QuellCorp and secretly funded the events in Oslo in the hopes of replacing his father as head of the company. Jasper wants to pin the blame for both QuellCorp and the murder of Martin on Andrew, but Jane refuses, threatening to reveal Jasper’s illegal activities if he ever contacts her again. She makes a deal with the FBI, preventing one of the bombings and leading to the arrest of Nick and Paula. After giving birth in prison during her reduced two-year prison sentence, Jane enters the Witness Protection Program, assumes the name Laura, and raises her daughter in Georgia.  

In the present, Andy meets Clara, who has lost much of her memory but helps Laura to connect some of the clues she has picked up on her journey. Slowly, the two narratives connect. Jane Queller is Laura Oliver and someone from her past sent Hoodie to attack her. Suddenly, Paula arrives at Clara’s farmhouse, kills Edwin, and shoots Andy, injuring her. On the phone with Laura, Paula threatens to kill Andy unless Laura meets them at a motel in Indiana with documents, originally collected by Nick, that provide evidence of Jasper’s illegal actions at QuellCorp. Paula’s plan is to blackmail or expose Jasper so that he can no longer block Nick from gaining parole and leaving prison. Paula tells Andy that she is the daughter of Laura and Nick, that she sent Hoodie to attack Laura, and that Mike is not a criminal but a U.S. marshal, assigned to monitor Laura.  

Later, in the motel, Laura arrives with the papers and Paula threatens to shoot and kill Andy unless Laura allows herself to be tied up. Andy, who has been bound and gagged, knows that Paula intends to kill Laura, and she nonverbally indicates to her mother that Paula has no more bullets, leading Laura to kill Paula with a hidden razor. In the epilogue, Laura visits Nick in jail with hidden microphones and baits him into admitting that he instructed Paula to send Hoodie after Laura, giving the police sufficient reason to ensure that he remains imprisoned.