In April 1953, Cussy Lovett, whose hereditary condition of methemoglobinemia gives her blue skin, is moved from the prison infirmary into the prison’s general population. She was imprisoned under anti-“miscegenation” laws (preventing sexual relationships and marriage between people of different races) for marrying Jackson, a white man. The sheriff’s deputy broke her arm during the arrest. During her month in the infirmary, she endured brutal examinations intended to “cure” her color. 

A guard leads Cussy through the prison, passing the Forensic, Geriatric, and Death Row wards. The guards mock her as a “crazy blue witch” and compare her to another inmate who was a “Melungeon” (6). As other prisoners refuse to be near her, Cussy is assigned a cot next to Waldeen Parker, an older inmate serving a life sentence for shooting a man. The guard assigns Cussy to kitchen duty, instructing Waldeen to have her there at four in the morning. Waldeen shows Cussy a photograph of a young boy before they sleep. Cussy grieves for her husband and worries about her daughter, Honey, who is in hiding. However, looking at Waldeen’s stack of books borrowed from the prison library, she feels hope for the first time since her arrest.

Drawing on her past as a Pack Horse librarian, Cussy asks Warden Sanders for the prison’s newly vacant librarian position. The warden rejects her request, noting that Cussy’s former doctor, Doc Thomas, persuaded the governor to get her out of the infirmary. As punishment for asking, the warden assigns Cussy double duty in the kitchen and the laundry room. Cussy struggles with the unfamiliar electric iron, and the abusive laundry supervisor, Estelle, punishes her for scorching an officer’s shirt. 

The librarian job is given to another inmate, Regina Miles. Cussy later witnesses Regina strike another inmate for damaging a book. When Cussy offers to repair the book cover, Regina insults her, calls her “Grape Stain,” and throws the book at her, earning a final warning from a guard.

After Regina is stripped of her library duties, Cussy hesitates to ask for the job again, fearing more punishment. In the kitchen, Waldeen praises Cussy for her resourcefulness in saving the prison money on food. Impressed by Waldeen’s report, Warden Sanders summons Cussy. The warden notes that while Cussy has cost the prison money by ruining clothes in the laundry, she has saved even more in the kitchen. Cussy explains her extensive experience as a WPA Pack Horse librarian, which intrigues the warden, who is desperate to raise the prison’s low literacy rate to protect its funding. The warden offers Cussy the librarian job temporarily, releasing her from laundry but keeping her on kitchen duties. She also mentions a future medical “procedure” with a Dr. Kennedy, which alarms Cussy. Recalling how the doctors sterilized her, she wonders what else they could want to do.

In the kitchen, Waldeen is forced to reassign Cussy to cleaning duties, preventing her from handling food because guards and inmates complain about her blue skin. 

Cussy finally opens the small, poorly stocked library and begins her work. She meets Buttermilk, an inmate from the men’s prison sent to make repairs. A kind war veteran with a leg injury, Buttermilk speaks French and gives Cussy the affectionate nickname “jolie bleue […] la fille de la montagne” or “pretty blue mountain girl” (29). He tells her he knows Jackson, who is doing well. Cussy feels a deep sense of joy and connection for the first time. However, as the days pass, no inmates visit the library.

Doc Thomas visits with news that Loretta, Cussy’s friend and former patron, has died. Doc says that since Honey no longer has a guardian, a lawyer is seeking her emancipation. Honey is 16 and works at the local library. 

Book donations begin to arrive, and Buttermilk continues improving the library space. Cussy finally works up the courage to ask Buttermilk to pass a written note to Jackson, but he kindly refuses as it is too risky. He tells her that he already conveys what he sees in her heart to Jackson. 

Warden Sanders inspects the library and is pleased with the progress but remarks on the lack of readers, increasing Cussy’s anxiety. After another week passes with no patrons, Cussy despairs that she will be fired and the library shut down. Remembering her work delivering books in the mountains, she decides to take matters into her own hands.

Cussy begins a mobile library service, first visiting the Geriatric Ward. Though initially met with fear and hostility, she wins the women over by reading aloud from Charlotte’s Web, and several become her first patrons. She is disturbed to see an inmate named Chaney who has been lobotomized. When another inmate, Marigold, is cruelly mistreated by a guard for soiling herself, Cussy intervenes to clean and comfort her. 

Next, she goes to Death Row and meets Sassyann, who asks to be taught to read and write so she can contact her sons before her execution. Sassyann confesses to poisoning her two abusive husbands. As Cussy leaves the ward, a hostile Regina stabs her hand with a sharpened pencil. Shocked by the brown color of Cussy’s blood, Regina calls her a “witch” and flees.

In the kitchen, Waldeen tends to Cussy’s wound and gives her a sharpened toothbrush hidden inside a hollowed-out book for self-defense. Waldeen then reveals her past as the infamous madam of a brothel. She explains that she took the fall for a murder committed by one of her workers, Clara. Clara had a son, William, who was “Blue” on his hands and feet, with a politician named Eldon Carter. When Eldon tried to take the child, Clara shot Eldon and fled. Waldeen raised William for the first two years of his life before Clara came and took him away. With astonishment, Cussy realizes her own connection to Waldeen’s story. Eldon was her uncle, and Clara’s son was Willie Moffitt, her former library patron. When Willie and his wife Angeline died, she adopted their daughter Honey.

Before Cussy heads to her next stop, the Forensic Ward, she recalls another inmate’s warning that lobotomies are performed on “crazy” and defiant women. She fears the doctors may try this on her.

Cussy enters the chaotic Forensic Ward, where the guard, Officer Frank Holt, warns her not to agitate the prisoners. While she reads, she is met with a mix of responses. One young woman, Emmeline, engages with her about The Wonderful Wizard of Oz, but Officer Holt violently stops their interaction, calling Emmeline a “firebug” who tried to kill a baby. Another inmate, Odette, recites Walt Whitman’s poetry before having a seizure. As Cussy continues to read, a deep quiet settles over the usually tumultuous ward, surprising even Officer Holt.