The murder of a former teen star from a '90s high school sitcom takes a strange turn when Beckett and McCord arrive at the 12th to take over the case and find a new detective at Beckett's desk on Castle.
Beckett: (Clears throat) Ahem. What's the deal with men and boobs, anyway? Castle: Biological. We can't help it. Beckett: But doesn't it bother you that they're so obviously not real? Castle: (Pauses) Santa's not real. We still love opening his presents.