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.

When Patrick Jane and the CBI must work with a criminal profiler, Dr. Montague, to solve a double murder, it becomes a competition for Jane to prove that his methods are superior.