The CBI mole's identity comes to light; the meeting of Patrick Jane and Red John has consequences for the team.
After a doctor is found dead at a golf course, the CBI team searches for a killer amongst a hospital’s staff and patients. Meanwhile, when LaRoche is placed in charge of the CBI, his first act of business is to name Cho the new team leader.
When the CBI investigates the murder of an antiques dealer found dead in a museum, the evidence indicates that the suspect may be a member of the team.
Van Pelt's actions are called into question and her position within the CBI is jeopardized when a witness is murdered while she is assigned to his protection. Eric Winter returns as FBI Agent Craig O'Laughlin, and Pruitt Taylor Vince returns as J.J. LaRoche, an investigator with the Professional Standards Unit.
The CBI pursues two lines of investigation when a Santa is murdered: Patrick Jane goes undercover in an AA group; and Rigsby and Van Pelt question members of the National Society of Authentic Santas. Meanwhile, following the demise of a person in custody at the CBI, J.J. LaRoche (guest star Pruitt Taylor Vince) is brought in to question the team when it appears to be an inside job. Guest star Gregory Itzen returns as retired former CBI director Vincent Minelli.