Sofia later punches the town's white mayor, an act that lands her in prison and snatches the independence she so values. By this time, she and Harpo have split up and taken other lovers, so the women in Sofia's life take on the responsibility of releasing her from jail. An alliance forms between Celie, Shug, Sofia's sisters, and Squeak, Harpo's mistress. When trying to help Sofia, Squeak is raped by her uncle, the prison warden, but in telling her friends about the rape, she becomes stronger, insisting that she will no longer be called by her nickname and beginning to compose her own blues music. Sofia is able to leave prison, but she finds herself caged nonetheless, working as a maid in a white household.
Meanwhile, Nettie has become a missionary in Africa and has written countless letters to Celie, all of which Albert has hidden. Nettie, in spite of her upbringing, is a self-confident, strong, faith-filled woman. When Celie discovers Nettie's letters, she not only catches up on her sister's life, she also discovers that her own two children are alive and living with a missionary couple with whom Nettie works. Nettie's letters about their shared African heritage are a tonic to Celie, who becomes stronger and more self-assured every day. That confidence soon turns to fury—over her rapes, her beatings, and the love and affection the men in her life have kept from her. Nettie's letters also demonstrate parallels between Celie's world and the African world, including the bond that can develop among the multiple wives of African men, the deep friendship and love that exists between two women, the deep love of a man for a woman, and the unrelenting structure of sex roles.
