The novel follows a seventeen-year-old girl whose family is in the U.S. Witness Protection Program, a federal program that gives new identities to endangered witnesses. At a safe house in the middle of the night, the narrator selects her latest fake first name, "Meg," after an actress on a muted TV screen. Her eleven-year-old sister, barely responsive after months of upheaval, agrees to be called "Mary." Agent Parker, their handler, assigns them the surname Jones. Meg's long blond hair is cut into a dark pixie style and dyed brown, and she receives contact lenses to hide her blue eyes. Staring at her unrecognizable reflection, she acknowledges the girl she used to be is gone.
The family's new placement is Natchitoches, Louisiana. Their father, now "Bill Jones," will work in an auto parts factory, a sharp demotion from his former career. Their mother is not assigned a job, which Meg suspects reflects her severe drinking. Meg demands to know what her father did to land them in this situation, but he refuses and storms out. They move into a shabby cottage, and Meg writes a set of rules: no clubs, no friends, no teams, and, most important, discover the truth.
At Natchitoches High School, Meg tries to remain invisible. She meets Ben Dufrene and Ethan Landry, a boy in camouflage with a dimple. A cheerleader named Emma mocks Meg's younger sister, whom the family calls Teeny, after witnessing one of her public meltdowns, and Meg retaliates by tripping Emma in class. Despite her rules, Ethan seeks Meg out where she eats lunch alone, and she finds herself drawn to him even as she tries to push him away.
Meg gets a job at a pizza restaurant run by Pearl, an older woman who turns out to be Ethan's aunt. Ethan spends evenings there, befriending Teeny and coaxing her out of her shell for the first time in months. Meg's resolve weakens, but she is alarmed when Pearl mentions that an unidentified man called asking about "Meg Jones."
The family continues to fracture. Meg's mother drinks more heavily each day, and her father grows increasingly paranoid. Meg presses both parents for answers, but her father stonewalls and her mother slaps her. Late at night, Meg overhears her father whispering on the phone about finding something and negotiating for the family's safety.
A man who identifies himself as Agent Thomas, young and well-dressed, begins appearing in Meg's life. He buys her a latte after she skips class and covers her absence with the school. When Meg asks why no one will explain her situation, Thomas says, "I'm sure if you think hard enough, you can figure some of it out." He later warns that another relocation would mean a permanent safe house with constant surveillance.
Meg and Ethan grow closer; she learns that Ethan and Emma are twins, and Ethan kisses her in a hidden stairwell. But strange incidents unsettle her: her go-bag, a duffel she keeps packed for sudden relocation, is opened at a party. Her journal vanishes from the laundry room after the power mysteriously cuts out. A black Suburban idles near her cottage.
One Sunday, Ethan takes Meg hog hunting on the farm. When a feral hog attacks his dog, Ethan shoots it. The crack of the gun and the spray of blood trigger a return of repressed memories: a room with stone walls, two men fighting, a gun firing, a teenage boy falling. Meg screams and blacks out.
That night, her heavily intoxicated mother delivers a bombshell: "You're why we're here. You're the one they're after." She explains that Meg witnessed something terrible and that the trauma caused her to forget. Over the following days, her full memory returns. Her real name is Anna Boyd, and her family lived in Scottsdale, Arizona. On the night everything changed, she went to the home of her father's boss, Mr. Price. She found Mr. Price in his office hiding thin ledger books inside a hollowed-out stone in the wall, then dove behind a couch when she heard someone enter.
Eduardo Sanchez, a man with a scar through his left eye, entered and demanded the ledgers. The books documented Sanchez's money laundering for a Mexican drug cartel. Sanchez shot Mr. Price dead. Brandon, Mr. Price's teenage son, walked in moments later, and Sanchez shot him too. When Sanchez found Anna hiding, she blurted out, "I know where the ledgers are!" to stop him from killing her. Sirens sounded and Sanchez fled. Anna had lied: She did not know the ledgers' location. But Sanchez believes she can lead him to the evidence he needs to destroy.
Anna's father explains that the FBI never found the accounting records and has only Anna connecting Sanchez to the murders. He blocked therapy to restore her memory, wanting to protect her, but reveals that someone connected to Sanchez has known the family's location in every placement, threatening their lives.
When Anna returns to school, she watches a girl remove a loose brick from a bathroom wall. The sight triggers her final memory: Mr. Price concealing the ledgers behind a removable stone in his office. Anna realizes they are likely still hidden there and begins planning a trip to Scottsdale.
Her plan collapses when agents arrive to relocate the family; her mother, drunk, called the agents and revealed that Anna's memory has returned. Anna packs essentials, hides a note for her father, and climbs out the bedroom window. Ethan, who had been watching the cottage, tracks her via a GPS device he loaned her. She tells him her real name and her need to reach Scottsdale. Pearl provides cash and an untraceable car. Ethan enlists Ben, his former rival, to create a false trail, and they drive west.
In Scottsdale, Anna enlists her old friends Elle and Laura to smuggle her and Ethan past security into the gated neighborhood where the Price house stands. Inside the office, they pry the stone from the wall and find the ledger books. Ethan drops his GPS tracker into the bag as a precaution. Agent Thomas walks in, claims Sanchez was killed in a raid, and asks for the ledgers. Anna hands them over, but Thomas disappears. They find Elle and the housekeeper bound and unconscious outside.
Agent Williams, the FBI's lead agent on the case, arrives after Laura calls the police. Williams reveals Thomas was never a legitimate agent: His business card is a high-quality fake, and a real agent would never approach a minor alone. Agents track Ethan's GPS signal to Sanchez's home, where they find Sanchez freshly murdered with the tracker in his pocket. The ledgers are gone, presumably delivered to the cartel. With Sanchez dead, no one remains to testify against, and the cartel has no reason to pursue Anna. The family is released from the program.
Three weeks later, the Boyd family settles permanently in Natchitoches under their real names. Teeny is improving, and Anna's mother is at a treatment facility. Anna and Ethan attend the Mardi Gras Ball, and for the first time, Anna feels she has a normal life. At the after-party, she discovers her stolen journal in her coat pocket with a daisy pressed between the pages, matching the small tattoo on her shoulder. A handwritten note reads: "I thought it was important for you to have this back. Maybe one day we'll meet again. —T." A postscript adds: "Tell your friend the tracker was a clever move." Anna tears the note apart and scans the crowd, but Thomas is nowhere to be seen. The novel ends with Anna in Ethan's arms, knowing that despite everything she has gained, she will spend the rest of her life looking over her shoulder.