The BAU travels to Los Angeles in search of an UnSub who kidnaps a nanny and the baby in its care every year. While the baby has always turned up alive within a day, the nanny is usually killed and the body prominently displayed - always on the same date every year. While JJ and Morgan go to Seattle in the hopes of gathering clues from the one nanny who managed to escape the UnSub's clutches, the rest of the team searches LA for the killer. When the latest kidnapped baby doesn't turn up within a day, however, the BAU is forced to wonder why their target changed his MO - and what that means for his latest victims.