Reese and Finch are on the case of a two-year-old unsolved murder after receiving the social security number of a girl named Teresa, who has been presumed dead since her father murdered his family and committed suicide. Could the machine have made a mistake? Finch insists not, charging Reese with the unenviable job of saving the life of a ghost.
Reese kicks off his investigation by strong-arming his friend, Detective Lionel Fusco, to hand over the file on Teresa's case, discovering in the process that what appeared to be a murder suicide was in fact the work of a professional hit man. A chat with the real perpetrator, who is now locked up in prison, vindicates Finch's faith that the girl must still be alive. But can Reese track her down before someone really does kill her?