A prologue establishes the historical circumstances of the novel's premise. On May 19, 1536, Anne Boleyn, second wife of King Henry VIII, was beheaded at the Tower of London on charges of adultery, incest, and high treason. Five men accused of being her lovers, including her brother George Boleyn, were executed two days earlier. Anne and Henry had courted for seven years while he pursued an annulment from his first wife, Katherine of Aragon, a conflict that led to England's break with the Catholic Church. During their marriage, Anne bore one daughter, the Princess Elizabeth, and suffered multiple miscarriages. Henry was openly involved with his mistress, Jane Seymour, to whom he became betrothed the day after Anne's death. Most historians agree Anne was innocent of all charges.
The novel begins when Anne regains consciousness inside a wooden arrow chest in St. Peter ad Vincula, the Tower chapel. In total darkness, wrapped in bloody linen, she pieces together her situation: She has been beheaded, and her head rests beside her knees. She unwraps her body, unwraps her head, and pushes open the lid. Carrying her head under one arm, she flees the chapel, crosses the Tower grounds, slips through River Gate, and drifts down the Thames in the jailer's boat.
Anne wakes at dawn in Southwark, a borough on the south bank known for its lawlessness and brothels. She steals a sewing basket from a tavern and sews her head back onto her neck. As she stitches, the wound heals through some unexplained magic: Her pulse returns, her heart begins beating, and her breath normalizes. She fashions a collar from Elizabeth's silk swaddling cloth, which she had hidden in her bodice before the execution, to conceal the scar. She strips off her bloodied gown and ventures into the streets in her red kirtle, a skirted underdress, penniless and hungry.
Extended flashbacks recall Anne's reformist religious convictions, her brother George's loving companionship, and the long courtship with Henry. She remembers how Henry once gave her a book of hours, a lavishly illustrated prayer book, identical to copies he gave Katherine and his advisor Thomas Cromwell. At a bearbaiting arena, a stranger named John pays her admission. Watching a blind, scarred bear goaded and slain crystallizes her resolve: Henry is wild and dangerous, and she must kill him to protect Elizabeth and secure the throne. After a sexual encounter with John by the river, she steals his money while he sleeps.
Anne meets Alice, a copper-haired woman from the fenlands, a marshy region in eastern England, who works periodically as a prostitute to earn money for her children. Alice drives John away at knifepoint when he demands his money back. Anne spins a half-true story: She has fled an abusive husband who tried to kill her and must cross London Bridge to rescue her daughter. Alice agrees to escort her for a day in exchange for five pounds, lends Anne a gray gown, and the two set off.
At the bridge's southern gate, Anne sees five tarred heads on pikes, one of them George's, and is overcome with grief. A flashback to their joint trial reveals Cromwell's fabricated charges, her Uncle Norfolk on the jury, and George's wife Jane testifying against them. After both were convicted, George mouthed "Be bold" to Anne. On the bridge, the two women grow closer. At the Chapel of St. Thomas, they argue about the dead queen's legacy, with Alice calling Anne Boleyn "the great whore" while Anne pushes back. Anne suffers a severe panic attack during prayer and faints; a kind priest tends to her.
After crossing into London, Anne sneaks into the Tower at twilight. She steals 10 pounds from the mint and retrieves jewels she had hidden for Elizabeth: a ruby ring, an onyx pendant, and a sapphire diadem. Thomas Wyatt, her imprisoned childhood friend and poet, spots her through a window, while Constable Kingston, her former jailer, shouts that she is the queen's ghost. With guards in pursuit, Anne leaps into the Thames. Alice dives in and drags her to shore. The two women flee to Shoreditch, where they argue bitterly; Anne threatens to blame Alice if caught, then regrets her cruelty and pays Alice the promised five pounds. Alice proposes they flee north, and Anne reluctantly agrees.
In the fens, Alice's brother rows them to a small island where a child minder named Ethel watches Alice's two children. Anne and Alice forage together, and Anne suffers fevers. One evening, a fairy tale about beheading triggers a panic attack. Alice comforts Anne and insists on seeing beneath the collar. She cuts the stitches and discovers the scar. Anne confesses she is the dead queen, and the two women kiss. They talk through the night, sharing their full stories. In the morning, Anne hides the ruby ring and onyx pendant in Alice's boots as parting gifts. She tells Alice she must leave to kill Henry. Alice begs her to stay, offering a life together, but Anne insists she must protect Elizabeth. Alice gives her a ribbon as a keepsake, and they kiss goodbye.
Walking south, Anne is joined by a white bull with a gold ring in its nose, whom she names Zeus. At an outlaw encampment, the leader, Simon, attacks Anne in the night, tears off her collar, and declares she is the dead queen. Zeus gores Simon to death, and Anne rides the bull onward. At a pond, she discovers a sword embedded in the mud, pulls it free, and continues toward London.
Anne retraces her coronation route to Whitehall Palace and infiltrates through the servants' quarters. She takes one of her own former gowns from Jane Seymour's chambers, rearranges the king's cutlery into the letter "A," and turns portraits of his ancestors upside down. When a servant recognizes her and raises the alarm, Anne flees into the hedge labyrinth, a maze she and Henry designed together, and hides in a secret chamber at its center. The next day, she encounters Cromwell on the riverbank and tells him she has come to kill the king, arguing that Henry will turn on Cromwell too. She asks him to serve as regent for Elizabeth. Cromwell replies that he will not help her but will not stand in her way. Anne returns to the palace and hides behind a door in Henry's chambers. She watches Henry enter with his men; as they leave, Henry turns, sees Anne, and blanches, but his companions push him along before he can react.
Anne conceals herself inside the hollow altar in Henry's private chapel and waits through the evening feast. Henry enters alone for his nightly prayers. Anne steps out with her sword raised. Henry pleads, offering to take her back and raise Elizabeth as his heir. Anne recalls all his betrayals and cruelty. She swings the sword and beheads him in one blow.
As the groomsmen approach, Anne's body transforms: White feathers erupt from her skin, her arms become wings, and she shrinks into a white gyrfalcon, a large falcon that served as her coronation emblem. She flies out the chapel window, leaving behind Henry's body, the silk swaddling cloth, and the sapphire diadem for Elizabeth.
Anne flies north to Hatfield Palace, where she finds Elizabeth sleeping. Transforming back into human form, she wakes the child, who recognizes her and says she knew her mother would come back. Anne tells Elizabeth a fairy tale about a banished queen turned into a falcon who defeats an evil king so her daughter can rule. At dawn, Cromwell arrives to collect Elizabeth for her coronation. Anne kisses her sleeping daughter, transforms back into a falcon, and flies north to the fenlands. She sees Alice below, running and laughing with her children. Anne swoops low, feeling the human legs inside her talons that will carry her to Alice, knowing she will be safe and loved.