Dr. Frederick Chilton, the administrator of the Baltimore State Hospital for the Criminally Insane, asks the FBI for help after an inmate, Dr. Abel Gideon, kills one of his nursing staff and claims to be the Chesapeake Ripper. Both Will and Jack doubt Gideon’s assertions, yet he possesses information that only the Ripper could know. In the midst of their investigation, Jack is haunted by the memory of an old student at the academy, Miriam Lass, who disappeared while on the Ripper's trail.