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 come to town for the holidays while Buzz starts training as a back-up police officer.

Sanchez is put under the microscope when his mother's caregiver is found murdered.. Rusty is forced to take on Jack when he shows up at Sharon's condo acting recklessly.