After months of hunting a murderer dubbed the Thorn Killer, Detective Greg Carver is shot in his own home. His trusted partner, Ruth Lake, is alone with him, yet instead of calling for help, she rearranges the crime scene and wipes the room clean of prints. Awakening in the hospital, Carver has no memory of being shot, but is certain that his assailant is the Thorn Killer. Unable to go return to duty, Carver's obsession grows; one person knows the truth and she's not talking. She's also now leading the Thorn Killer investigation while Carver recuperates. It doesn't matter that more victims' lives are at stake—Ruth is keeping a deadly secret, and she'll cross every line to keep it from surfacing.