Carter Hastings

When a series of backyard pool homicides are reported in California, the BAU team searches for an UnSub with a puzzling past.

The team investigates the murder of someone from Booth and Brennan’s past. Meanwhile, Aubrey faces a moral dilemma of his own when he discovers his dad is back in the picture.

Santa finds himself on the naughty list after robbing a bank, but a Santa flash mob complicates his apprehension and the Major Crimes unit scrambles to figure out how things went so wrong. Sharon's kids (guest star Zarah Mahler and recurring guest star Ryan Kennedy) come to town for the holidays while Buzz starts training as a backup police officer. Recurring guest star Dawnn Lewis appears as Patrice. Lilli Birdsell, Annie Abrams and Carter Hastings also guest star.

When Polly is apprehensive about putting herself up for a promotion (wine and cheese manager) and Natalie announces that she's playing a "hillside" in the school play, Elaine and Max decide to get involved in order to make sure that Natalie and Polly are living up to their full potential.