Alex Frnka

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 this backdrop of Christmas, Esposito and Lanie reach a defining moment in their relationship.

The Jeffersonian team unravels an unexpectedly competitive world of mini-golf as they try to piece together the murder of the sport’s superstar. Meanwhile, Brennan is worried her father Max is reverting to his criminal tendencies and “squintern” Wendell Bray, enlists Hodgins to help him fix his girlfriend’s family heirloom.

A nefarious virus is uploaded to Walter's computer, turning the team's new "smart" building project into a death trap with people locked inside.