Set in Atlanta in November 1974, the novel opens before dawn as police officer Jimmy Lawson carries his mortally wounded partner, Don Wesley, 20 blocks through the empty streets to Grady Hospital. Don has been shot in the head in an alley near Five Points, the city's downtown intersection, by an assailant wielding a Raven MP-25, a cheap semiautomatic pistol. The gun jammed before the shooter could fire at Jimmy. Don dies moments after they crash through the emergency room doors.
At the Lawson family home in Grant Park, Jimmy's younger sister Maggie, a 23-year-old patrol officer, learns of Don's death. Maggie lives with her mother Delia, Jimmy, and her 13-year-old sister Lilly. Her uncle Terry Lawson, a police sergeant, arrives and reveals only sparse details. Maggie presses him: Four other officers have been executed in recent months by a serial killer the force calls the Atlanta Shooter, all shot on their knees. Don's killing shares similarities but also key differences, including slashed tires and Jimmy left unharmed. After everyone disperses, Maggie checks Jimmy's revolver and discovers every round is still loaded, contradicting his claim that he fired at the attacker.
Meanwhile, Kate Murphy, a 24-year-old widow whose husband Patrick was killed in Vietnam, prepares for her first day on the force. At the station, she endures harassment from male officers and hostility from the women. Terry assigns Kate to ride with Jimmy, who subjects her to a degrading tour of the city's worst neighborhoods. When a pimp sexually harasses her while Jimmy watches, Kate snaps, punches Jimmy, and kicks his bad knee out from under him, shocking him into grudging respect.
Woven between these chapters is the perspective of Fox, a stalker who has been surveilling Kate for weeks. Fox is a veteran shaped by a violently abusive childhood. His father, "Senior," beat his mother throughout her life; she later died of stomach cancer when Fox was 12. Senior botched his own suicide, and Fox finished it with a second bullet. Fox views Kate as a seductive "Jewess" hiding behind an Irish name and has soundproofed a room in his basement for her.
Maggie enlists Gail Patterson, a veteran plainclothes officer who had a secret relationship with Don, to investigate outside official channels. Among Don's belongings, Maggie finds a matchbook for a bar called Dabbler's, which provokes alarmed reactions. After Jimmy is shot in the arm while interrogating a snitch, Kate encounters Philip Van Zandt, an orthopedic surgeon, at Grady Hospital. Philip shows Kate Jimmy's X-ray: Fragments of Don's skull are embedded in Jimmy's thigh, proving Don's head was in Jimmy's lap when the gun fired and indicating the two men were engaged in a sexual act. Kate promises to keep the secret.
A visit to her parents' Buckhead home reveals Kate's family background. Her father Jacob is a prominent psychiatrist, her mother Liesbeth survived Auschwitz, and her grandmother Oma survived the Mauthausen concentration camp.
On the second day, Maggie, Kate, and Rick Anderson, a sympathetic detective, review the Shooter case files and discover critical parallels. Each victim was lured by an anonymous call, each requested a meal break just before being killed, and all had their radio mics deliberately unplugged. Kate notices one victim was dragged back to the kill site after trying to escape, explaining why the Shooter slashed Jimmy and Don's tires as an adaptation.
Maggie, Gail, and Kate visit a boardinghouse to meet Sir Chic, a pimp who controls the Whitehall prostitutes. Chic produces Jimmy's missing radio transmitter and begins to say the killer looks nothing like the man in the police sketch. Before he can finish, a rifle bullet from an abandoned building kills him, and the same shot clips Kate's ear. Chic's bodyguard Anthony tackles Gail and drives a switchblade into her eye; Maggie empties Kate's gun into Anthony's head. Gail survives but loses sight in that eye. Fox reveals himself as the sniper, having killed Chic to prevent identification. He has already kidnapped Jimmy and chained him in his basement, intending to use Jimmy as bait to lure Kate.
That evening, Terry finds a handwritten confession on Jimmy's bed in which Jimmy claims to be the Atlanta Shooter, stating he killed the other officers because he had sexual relationships with them and feared exposure. Terry's rage centers on Jimmy being gay; he announces he will kill Jimmy and stage it as a Shooter attack. When Maggie protests, Terry chokes her. Delia tears up the letter, but Maggie transcribes it from memory and leaves the house, searching Atlanta all night for her brother.
On the third day, a witness confirms the killer is a white man with a military build, contradicting Jimmy's description. At Dabbler's, which proves to be a gay bar where Jimmy is a regular, a man fitting a cop or soldier's profile recently visited. Kate reads the transcribed confession and argues it is false: The shrapnel in Jimmy's leg proves he was beside Don, not holding the gun, and the derogatory language sounds like someone else's words forced into Jimmy's mouth. Maggie reveals that eight years ago, Jimmy's friend Michael raped her, and Jimmy's anguished reaction suggested Michael was his lover. Kate and Maggie conclude the apology in the letter is a coded signal that the confession was coerced. At the hospital, Gail identifies a deeper pattern: Every Shooter victim defied the established order through interracial relationships, liberal politics, or countercultural sympathies. The killer targets officers he views as traitors to white male power.
Terry's voice crackles over the radio, reporting shots fired at the Howell Rail Yard. Maggie recognizes his calm tone and realizes he is staging Jimmy's execution. At the yard, they find another officer, Jake Coffee, murdered execution-style. When Maggie draws her gun on Terry, he punches her down. Kate strikes Terry with her nightstick; a rifle shot from the building behind them hits Terry in the stomach.
Maggie and Kate flee into the second building. Chip Bixby, a veteran officer and Army Ranger, appears and herds them up the stairwell, firing his revolver to keep them moving. Maggie realizes Chip is the Shooter. His partner Duke Abbott was murdered and the killer acquitted, which broke Chip. He has been executing officers he considers "vermin" for defying racial and social hierarchies.
On the roof, Jimmy lies bound nearby. Chip forces Maggie to her knees and taunts Kate with intimate details proving he has watched her sleep and entered her family's home. Patrick's stolen dog tags hang around his neck. Kate counts the shots fired in the stairwell and determines Chip's revolver is empty. She lunges for a discarded gun and shoots him in the shoulder. Chip draws the Raven MP-25, fires his last bullet at Maggie, and misses. Refusing to be arrested, he steps off the roof to his death.
Kate fabricates a story to protect Jimmy, insisting Chip confessed before dying that he had framed Jimmy and forced the confession. In her official report, she credits Maggie with the decisive tactical distraction. On the fourth day, Maggie visits Terry, now paralyzed, in the hospital. She tells him his planted evidence in a prior case set Chip off, then presses her hand toward his wound until he begs and apologizes. A week later, Kate and Maggie return to work as permanent partners. Kate publicly kisses Jimmy to undercut rumors about his sexuality. When a terrified new recruit stumbles into the locker room, Kate guides her through her first moments with the same words Maggie once said to Kate: "Welcome to the Atlanta Police Department."