Dr. Sarah Baldwin races to a Boston hospital with  a young woman whose normal labor has suddenly  become a matter of life and death. As she struggles to  save both mother and baby, she doesn't know that  two other women have already died under horrifying  identical circumstances. And so begins Sarah's own  nightmare, as she learns that the prenatal herbal  vitamins she prescribed are the only thing these  women have in common. Soon Sarah is fighting to  save her career, her reputation -- her life. For  she's certain there must be some unknown factor  linking these women, and as she gets closer to the  truth, it becomes clear that someone will do anything  -- even murder -- to keep a devastating secret.