An adopted child of an indeterminate race gains a greater appreciation of her place within her adoptive family. Macey lives in a racially diverse, struggling neighborhood in Philadelphia. Missing a thumb, she has been nicknamed "Niner" by her classmates. Her talented younger sister, Deena, is the natural child of their Irish American parents. Their mother has failed to return from a trip for almost a year and has not been in contact with the family for months. Macey cannot help but feel partly responsible: she did not turn out to be the "right" kind of adopted daughter, and from the color of her skin to her poor academics, she believes that she has never really fit in. She wonders who her birth parents are and worries that the genes she has inherited are controlling who she is and what she will become. Through a series of events, which all begin with the discovery of a broken locket on her front lawn, Macey comes to see that family bonds are more important than genes.