Grace and Susannah have grown up to be as opposite as sisters can be. Grace is smart, successful, and happily married—but the one thing missing from her seemingly perfect life is the baby she's unable to conceive. Beautiful Susannah is like a car crash in motion: Always in trouble, she's been estranged from the family since abandoning her two sons from a disastrous early marriage. When their mother falls suddenly and seriously ill, Grace reluctantly calls Susannah back home. As the two sisters try to repair their relationship, Grace realizes that Susannah might be the answer to her prayers: Her sister is willing to be her surrogate, to give birth to Grace's longed-for baby. But when Susannah makes a reckless choice that threatens her life and the baby's, how far will Grace go to save her sister if it means losing the one thing she wants most?