Virgil Wounded Horse is a hired vigilante on the Rosebud Indian Reservation in South Dakota, home to the Sicangu Lakota people. Federal prosecutors handle all felony crimes on the reservation but rarely pursue anything short of murder, so community members hire Virgil to deliver justice. The novel opens with Virgil waiting outside the Depot bar to beat Guv Yellowhawk, a school gym teacher who raped a nine-year-old student. Virgil, an
iyeska (mixed-blood Lakota) who was bullied as a child for his heritage, carries out the job for free, dislocating Guv's arm and breaking his teeth.
Virgil lives with his fourteen-year-old nephew, Nathan, who has been in his care since the death of Nathan's mother, Sybil, Virgil's sister, in a car accident three years earlier. Virgil has quit drinking and saves his earnings for Nathan's future education. His rejection of Lakota spiritual practices stems from childhood trauma: A medicine man told him to fast and pray in the woods to heal his father's pancreatic cancer, but Virgil returned after three days to find his father had died. Convinced the ceremonies were empty, he vowed never to trust Native rituals again.
Ben Short Bear, a tribal councilman and the father of Virgil's ex-girlfriend Marie Short Bear, approaches Virgil with a job. A student has died from a heroin overdose, and Ben believes Rick Crow is smuggling heroin from Denver. Tribal courts can only impose sentences of up to one year, and the feds lack evidence, so Ben offers Virgil five thousand dollars to stop Rick. Virgil declines, sensing something suspicious about the proposal, but investigates Rick's trailer on his own, finding drug paraphernalia and a notebook linked to a cannabis dispensary in Denver. He attends a sweat lodge led by Jerome Iron Shell, a medicine man, and dreams of Sybil telling him to "remember the birds" and "the lost bird." The phrase echoes the winter count, a traditional Lakota pictographic calendar, they drew as children to represent the year their mother died.
The crisis becomes personal when Virgil comes home to find Nathan unconscious with gray-blue skin and heroin paraphernalia on the floor. The heroin was likely cut with fentanyl, a synthetic opioid fifty times more potent than heroin. Nathan flatlines but is revived, though one lung collapses, and doctors cannot determine whether he has sustained brain damage. Virgil accepts Ben's job. Marie contacts Virgil at the hospital, revealing she dated Rick briefly and knows where he stays in Denver. She insists on joining Virgil, claiming she has leverage over Rick. Virgil leaves Nathan at his elderly Auntie Audrey's house to recover and drives to Denver with Marie.
In Denver, they search for Rick without success. Outside a bar frequented by the Aztec Kingz, the gang Rick works with, they encounter Dennis, an undercover Denver police officer. Dennis explains how Mexican cartels recruit Native Americans to sell heroin on reservations, where outsiders would stand out, and proposes using Nathan as a confidential informant. Virgil refuses. At the Denver Indian Center, they learn from Rick's father, Reuben, about Rick's traumatic childhood. Marie tells Virgil that Rick experienced sexual abuse as a child and hit her when she tried to discuss it, ending their relationship. Virgil and Marie reconnect romantically, tentatively rebuilding what they lost.
Their trip is cut short when Virgil's friend Tommy, recently released from prison, calls to report that oxycodone pills have been found in Nathan's school locker after an anonymous tip. Nathan faces a felony charge carrying up to fifteen years. Virgil and Marie rush home. Ben connects Virgil with Charley Leader Charge, a Native defense attorney who takes Nathan's case pro bono. The prosecutors offer a deal: If Nathan cooperates as a confidential informant, wearing a wire to buy drugs, his case stays in the juvenile system and the charges are dropped. Otherwise, he faces a minimum of ten years with no parole and trial as an adult before a predominantly white jury. After consulting Jerome, who speaks of Lakota justice as putting the
oyate (people) first, Virgil advises Nathan to take the deal. Nathan reluctantly agrees.
Meanwhile, Marie is accepted to the University of New Mexico medical school but must commit to five years of practice in New Mexico. Her supervisor, Delia Kills in Water, fires her from her tribal family services job. Suspicious about misuse of a federal bison grant, Marie breaks into Delia's office and discovers approximately $150,000 funneled through fake invoices to the company of Chef Lack Strongbow, a prominent indigenous chef. Devastated, Marie decides not to report the apparent fraud.
Nathan completes a preliminary drug purchase to establish credibility with the dealers. For the recorded buy, Dennis fits him with a hidden listening device and sends him to meet the dealers after school. The operation collapses when the dealers drive off with Nathan. The follow car loses them. Nathan manages one call using the emergency code before the line goes dead. The gang's car is found abandoned with Nathan's phone crushed beside it.
Virgil searches desperately but finds no leads. Marie persuades him to attend a
yuwipi, a traditional Lakota healing ceremony conducted in total darkness with drumming and prayer. Virgil has a vivid vision of the 1890 Wounded Knee massacre, watching soldiers fire on unarmed Lakota men, women, and children. In the vision he sees a baby, "the lost bird," and Nathan leads him into a building he recognizes as the abandoned museum at the massacre site on the Pine Ridge reservation.
At the darkened museum, Virgil finds Rick Crow and extracts the truth through violent coercion. Ben has been running a pain pill operation on the reservation for years, using Guv to distribute. Guv planted the pills in Nathan's locker to frame him, forcing Nathan into service as an informant against the rival heroin gang, Ben's competition. The gang discovered Nathan was an informant and took him to an old slaughterhouse in Porcupine to kill him. Virgil considers executing Rick but stops when he has a vision of Sybil urging forgiveness. Ben then enters, confirms everything, and shoots Rick dead. He reveals he has tracked Virgil by GPS, had Delia fire Marie, and plans to kill Virgil and blame the heroin gang. Marie, who followed Ben's car, appears with a revolver and shoots her father to save Virgil.
Virgil storms the slaughterhouse and finds Nathan in the basement, tied to a chair with burn marks on his body. Virgil kills two gang members in the firefight but runs out of ammunition. The enforcer, Loco, gets Virgil in a chokehold. Nathan, still bound, kicks a cattle prod within reach, and Virgil breaks free and kills Loco with it. Shot in the shoulder, Virgil collapses from blood loss.
Nine months later, all charges against Nathan are dropped. Guv confesses and receives fifteen years. An investigation reveals Delia was working with Ben, not Lack, to defraud the government; Lack is cleared. Marie declines medical school and stays on the reservation as head chef at the new casino restaurant. Nathan transfers to a new school, joins the cross-country team, and starts dating. At a naming ceremony, Nathan receives the Lakota spirit name Tatanka Ohitika (Brave Buffalo) and Virgil receives Tatanka Ta Oyate (Buffalo Nation), honoring them as protectors of the community. An elderly woman approaches Virgil, asking him to find her kidnapped granddaughter, a case the federal authorities have declined to pursue. The novel ends with Virgil considering whether to take the job, suggesting his work will continue, now informed by a deeper connection to his heritage and community.