Mercy (atlee Pine, #4)

The novel opens as FBI Special Agent Atlee Pine watches the exhumation of a coffin from a rural Virginia grave. Pine, a tall, muscular agent normally stationed near the Grand Canyon, is on personal leave with her administrative assistant, Carol Blum, to search for her twin sister, Mercy Pine. Mercy was abducted from their shared bedroom in Andersonville, Georgia, when the girls were six. The kidnapper, Ito Vincenzo, shattered Pine's skull before taking Mercy, acting at the urging of his mobster brother, Bruno, who held a grudge against the girls' mother, Julia, for her role as a government mole that helped dismantle several New York crime families.

Pine and Blum trace Mercy's captivity to Crawfordville, Georgia, where she was imprisoned by Joe and Desiree Atkins under the name Rebecca Atkins until she escaped nearly two decades ago. Joe was found stabbed to death the day after, and Desiree vanished. Pine believes the exhumed body is Vincenzo, not Tim Pine, the man she believed was her father; she learns her biological father is Jack Lineberry, a wealthy financier. She suspects Tim faked his death and Julia joined him in hiding. Lineberry provides Pine with financial resources and a letter Julia wrote years earlier expressing guilt over Mercy's abduction and her decision to leave Pine.

The narrative shifts to reveal that Mercy is alive, living under the name Eloise "El" Cain. Six foot one with a nearly shaved head and scarred physique, she fights in underground mixed martial arts cage matches and works multiple low-paying jobs. She gives away over half her fight winnings to homeless families. Her only memory before captivity is a fragment: a girl telling a woman not to be mad at someone named "Lee" in a tree. When an FBI public service announcement about "Rebecca Atkins" airs, Cain is terrified but relieved her current appearance is unrecognizable from the surveillance photo.

After being evicted, Cain intervenes at a motel when Ken Buckley, a man with a tattoo from the Aryan Brotherhood, a white-supremacist prison gang, beats his girlfriend Rosa. Ken attacks Cain with a knife and gun, but she disarms and subdues him. She takes Rosa to a women's shelter. Ken's wealthy older brother, Peter Buckley, a criminal entrepreneur whose father's violent separatist compound was destroyed by federal agents, begins hunting Cain after Ken dies of a brain aneurysm. He recruits Britt Spector, a former Army paratrooper and ex-FBI agent who works as a contract killer.

Pine and Blum confront Wanda Atkins, Joe's frail mother, in Huntsville, Alabama. Wanda admits she knew about Mercy's underground imprisonment but never freed her, and she helped Desiree flee the night Joe was killed. Pine traces Desiree's phone number to Asheville, North Carolina, where she finds Desiree's occult shop and home. Beneath the house, Pine discovers Gail, a terrified 13-year-old whom Desiree has imprisoned in a crawl space. When Desiree arrives and threatens Blum at gunpoint, Gail attacks Desiree, allowing Pine to seize the weapon. Blum then draws Desiree into a recorded confession: She tortured Mercy for years and killed Joe on the night Mercy escaped, when Joe tried to let Mercy go. Desiree is arrested.

Cain drives south to confront her past, revisiting her underground prison in Crawfordville and retrieving her childhood doll. She confronts Wanda in Huntsville, who reveals that Cain's real name is Mercy, that she was kidnapped by Vincenzo, and that she has a twin sister. Wanda adds that Joe died from a knife wound, not the head injury Cain believed she caused, relieving Cain of guilt she has carried for years. Cain traces Desiree to Asheville and learns she has already been arrested. At the same hotel where Pine is staying, the sisters nearly cross paths: Pine noticed a tall, shaved-headed woman in the hotel gym earlier, and when Wanda calls to describe Mercy's appearance, Pine realizes the woman was her sister. She races to room 404 but finds it empty. That night, Buckley's men abduct Pine from the hotel, mistaking her for Cain.

The next morning, Blum encounters Cain in the hotel gym and reveals that Cain's twin sister, FBI Agent Atlee Pine, has been kidnapped. Mercy is skeptical until Blum shows a childhood Polaroid and recites "eeny, meeny, miny, moe," triggering suppressed memories. They visit Desiree in jail and trace a lead to a large house where Mercy glimpses Buckley, but the occupants flee and Spector abducts Blum. Pine escapes her captors by breaking apart her chair and overpowering two guards. Back at the hotel, Mercy walks through the revolving door as Pine exits. Pine says her name. Mercy responds, "Lee? Is that really you?" They embrace for the first time in 30 years.

The reunion is fraught. Mercy erupts in a raw monologue, revealing the extent of Desiree's torture and recounting years of exploitation and substance addiction after escaping. She storms out but returns, asking, "How do we find Carol?" After five days with no leads, the sisters and FBI Agent Neil Bertrand drive to Huntsville to revisit Wanda, but the trip is a trap: Wanda and her husband Len are dead, Bertrand is killed, and the house is ablaze. The sisters are knocked unconscious at their car, where Buckley's men lie in wait. They awaken in a cell at Buckley's rebuilt separatist compound in remote Idaho. Buckley announces they must fight each other in a cage; if he deems them insufficiently aggressive, a guard will cut Blum with a knife. The winner lives and the loser dies; if neither wins, all three women die. In their cell, Pine breaks down, and Mercy comforts her: "This time we're both up that tree, but you're going to get us back down."

During the match, Spector serves as referee and secretly whispers instructions to the sisters. At the final round's thirty-second mark, Mercy kicks Pine against the fence, drawing all eyes. Spector shoots the man guarding Blum and detonates flash bang grenades among Buckley's men. The sisters, eyes closed and earplugs in, recover quickly. Mercy lifts Blum over her shoulder, and they flee in an Escalade Spector prepared. When gunfire punctures the gas tank, they make a stand in a box canyon. Mercy devises a final stratagem: She tapes a walkie-talkie inside the SUV to broadcast staged screams from cover, then lights a fuse to the remaining fuel. Buckley's men fire on the vehicle, believing the women are inside, and the SUV explodes. The women kill the remaining attackers. As Buckley rises behind Mercy with a shotgun, Pine shoots him dead.

Pine allows Spector to escape before the FBI arrives, calling her an "honorary sister." Back east, the Tim Pine investigation closes after a federal agency confirms Tim acted in self-defense against Vincenzo. At Lineberry's estate, Lineberry reveals to Mercy what he never told Pine: Julia did not voluntarily stop searching for Mercy. A corrupt government official threatened to expose the family's location to remaining mob figures if Julia continued, forcing her underground to protect Pine.

Lineberry flies the group to Savannah, Georgia, and leads them to a cemetery. Julia Pine steps out from behind a mausoleum, touches Mercy's cheek, and says she never thought she would see her again. She recognized Mercy from the FBI's broadcast and called Lineberry to arrange the reunion. She reveals that Tim, living under the name Mark Douglas, was killed by a drunk driver. Mercy asks why she was named Mercy. Julia answers: She was the first twin born after two days of labor. "It was just the first word that came to my mind." Blum and Lineberry step away, and the three Pine women walk arm in arm toward the setting sun.