The latest inmate to enter Horizon House is Lynn Ingram, a transsexual who was convicted of manslaughter but always claimed self-defense. Her trial a few years earlier was a media circus, and the press attention has started back up since the news of her transfer. Furthermore, since Ingram's prison term was characterized by violence, Nat and her staff are preparing for the worst from both inside and outside the house.

Just days into her transfer, Lynn is beaten into a coma. Nat is fiercely determined to protect her charge and discover what happened, and begins to look deeper into Lynn's life with the help of Boston Homicide Detective Leo Coscarelli, with whom Nat is more emotionally involved than maybe she should be, seeing as how the mother of Leo's child is also one of the inmates at Horizon House.

Before they can get very far in their investigation, though, it begins to seem that Natalie and Leo have a determined killer on their hands, and more than Lynn's life is at stake.