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.
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.
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.
When she loses out on her dream job Ronnie quits (for a while) and gets drunk with a passenger. Pilot Dave finds his charm misses its female targets, but he does manage to hit a disruptive passenger.