In this crime series, a crack team of F.B.I. profilers fly from Quantico to the focal point of the criminal activity of various serial killers. There they investigate the evidence from the crime scenes, compose a profile, and try to prevent the next fatal strike. Top brain was academic Jason Gideon (Mandy Patinkin), who left the bureau after some difficult decisions. His more by-the-book operational right hand man Aaron "Hotch" Hotchner (Thomas Gibson) then took over the team. After Gideon leaves, David Rossi (Joe Mantegna), previously retired, rejoins the bureau in an effort to make a difference in people's lives again and follow-up on a case he worked years ago. The still juvenile Dr. Spencer Reid (Matthew Gray Gubler) is an erudite on everything except real-life, Penelope Garcia (Kirsten Vangsness), a brilliant computer whiz who gets access to any database, et cetera. As they are mobile, cooperation with local Police and F.B.I. Agents is important, but often poses jurisdictional and other problems, as do some witnesses and suspects.