Claire Waters is a dedicated forensic psychiatrist with unnervingly personal insights into the criminal mind. Haunted by a disturbing childhood incident, Claire has always been drawn to those rare "untreatable" patients who seem to have no conscience or fear. Quimby is a deranged inmate whose boyish good looks hide a sordid history of dysfunction and abuse, and he triggers something in Claire she'd rather not face. As she tries to unlock Quimby's past, she leaves herself dangerously vulnerable. When the case propels her into the mind of another killer - a homicidal maniac who's watching her every move - it could only end in madness, or murder, or both.