Bad Santa

"Bad Santa" is the tenth episode of Castle season 7 that airdate on December 8, 2014, was written by Chad Gomez Creasey and Dara Resnik Creasey and directed by Bill Roe.

Synposis
When an ER physician is gunned down in the street, Castle and Beckett soon discover that the victim was a mob doctor to a Mafia family run by an old friend of Castle's. Also, against the backdrop of Christmas, Esposito and Lanie reach a defining moment in their relationship.