Seventeen-year-old Annabelle is going to have a baby by a boy who wants no part of it, or her. Unwed and pregnant - the worst catastrophe to befall a middle class, Catholic girl in the 1960's. Desperate to hide their daughter's condition from friends and neighbors, her parents send her to live with strangers. When Annabelle gives birth to a boy, her father, a man who has sired three girls but yearns for a son, decides that he and his wife will raise the child as their own. He forces Annabelle to pretend to be the baby's sister.