For San Francisco homicide detective Valerie Hart, their trail of corpses - women abducted, tortured and left with a seemingly random series of objects inside them - has brought her from obsession to the edge of physical and psychological destruction. And she's losing hope of making a breakthrough before that happens.
But the slaughter at the Cooper farmhouse didn't quite go according to plan. There was a survivor, Rowena's 10-year-old daughter Nell, who now holds the key to the killings. Injured, half-frozen, terrified, Nell has only one place to go. And that place could be even more terrifying than what she's running from.
To stop the slaughter, Valerie has no choice. She must ask Katherine Glass to help her decipher the killer’s twisted message. But that means re-entering the pitch-black labyrinth that is Katherine’s mind, and this time Valerie isn’t so sure which one of them will survive.