Haunted by a disturbing childhood incident, Dr. Claire Waters is drawn to those "untreatable" patients who seem to have no conscience or fear. In a holding cell at Rikers Island, where the young forensic psychiatrist meets with a dangerous inmate whose boyish looks mask a sordid history of violence, her daring methods reveal a key to her own dark past. And when the case propels her into the mind of a homicidal maniac watching her every move, the only way to stop a killer from killing again is to go beyond the edge of reason...