Kay Scarpetta has arranged to meet an inmate at the high-security Georgia Prison for Women. The prisoner is a convicted sex offender and the mother of a vicious and diabolically brilliant killer.

Against advice, Scarpetta is determined to hear this woman out - she believes she may hold some answers to the murder of her former deputy. But soon she finds connections to a string of grisly killings, including the slaughter of a Savannah family years earlier. She can see a pattern to these killings, but who is behind them and why?

As she learns more, Scarpetta is compelled to conclude that this is only the beginning of something far more destructive: a terrifying terrain of conspiracy and potential terrorism on an international scale. And she is the only one who can stop it...