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 an authentic Santa society. Meanwhile, following the demise of a person in custody at the CBI, J.J. LaRoche is brought in to question the team when it appears to be an inside job.
Patrick and the team investigate the murder of a woman with ties to one of the fighters. Meanwhile, LaRoche focuses his investigation on Rigsby, who in turn is forced to ask Cho for a huge favor in order to keep his job.
After a young violinist is shot to death, Patrick Jane questions the members of the Northern California Symphony Orchestra about the murder. Meanwhile, Cho crosses paths with a precocious young pickpocket.