While her father Ray is away on an extended business trip, eight-year-old Roberta "Bobby" Carter and her school friends see her mother Joan kissing a stranger in a public park. Although Bobby refuses to admit to the other children that her mother has a "boyfriend," she is deeply disturbed by what she has witnessed. That night, Ray returns home unexpectedly from his trip and gives the delighted Bobby a toy piano, which plays "Home Sweet Home." After Bobby goes to bed, Joan tries to tell Ray about her affair, but is unable to break the news to him. Later, at a playground, Bobby is again teased by her friends about her mother's behavior. After chasing away her tormenters, the sensitive little girl tearfully asks God to make her parents love each other. Joan, however, continues her affair until a suspicious Ray finally asks her about her frequent absences. Thus confronted, Joan admits that she is love with a man named Michael Benton and wants a divorce. Stunned, Ray rails against his wife and slaps her across the face as a confused and frightened Bobby spies on her parents in the doorway. Upset by Ray's outburst, Joan runs to the park and is followed by a hysterical Bobby. Although Bobby seeks reassurance from her mother, Joan tells her that she is leaving home that night and is taking her away from her father. Later, at her parents' divorce trial, Bobby is asked to testify, but she is unable to condemn either parent. The judge grants the Carters a divorce and gives Joan custody of Bobby during the school year and Ray custody for the summer months. After Joan and Michael marry, Michael attempts to win over his step-daughter, but Bobby continually resists his overtures. Then, just before Bobby is to return to her father, Michael confronts Joan about the situation and suggests that the girl is causing a rift in their marriage. Although Joan implores Bobby to give Michael a chance, Bobby cannot accept her new "father" and tells her mother that she is not sure if she wants to return to her in the fall. Bobby's joy at being reunited with her father is abruptly curtailed, however, when she is suddenly introduced to his fiancée, Louise Norman. After Bobby falls sick with grief, her doctor informs Ray and Joan that she needs more continuity in her life and advises that one of them should assume sole custody of her. As neither parent feels capable of making Bobby happy, the child is sent to a country boarding school. There, on visitors' day, a lonely Bobby waits for the arrival of her parents, who are to visit her separately. After Ray, who has since remarried, cuts short his visit, Bobby is reassured by her wise, young roommate, whose parents also are divorced, that she will eventually "get used to" being alone. Then, as the school's church bells play "Home Sweet Home," Bobby sadly ponders her future and vows that when she grows up and gets married, she will put her own little girl to bed every night.