Criminal Minds tells the story of the Behavioral Analysis Unit (BAU) under the FBI headquarters. Behavioral analysts analyze the most difficult cases, analyze the psychology and characteristics of the murderer, and predict their next move before they commit violence again, assisting the local police in catching the murderer. During the early filming of this season, Hotch, the leader of the show, was fired by the crew because of a conflict with the screenwriter, so he will only appear in the first two episodes of this season. In order to make up for the departure of the protagonist, CBS will introduce two new characters, and at the same time promote Paget Brewster, who plays Emily, to a regular actor this season. At the same time, Jane Lynch, who plays Reid's mother, will also return in the twelfth season.