After moving from Chicago to Dallas in the spring of her sophomore year, fifteen-year-old Ella finds that joining the softball team at her private school not only helps her make friends, it also provides unexpected opportunities to learn and grow.

"In the near-future United States, a one-child policy is ruthlessly enforced. Everyone follows the Rule of One. But Ava Goodwin, daughter of the head of the Texas Family Planning Division, has a secret--one her mother died to keep and her father has helped to hide for her entire life. She has an identical twin sister, Mira. For eighteen years Ava and Mira have lived as one, trading places day after day, maintaining an interchangeable existence down...