When Alexis discusses a suspect with Castle, Ryan, and Esposito, she mentions that he is a notorious playboy who is "already on wife number three", to which Castle replies "You say that like it's a bad thing". Beckett, his own wife number three, is the woman Castle professes to be the love of his life.
Beckett picks a bit of red confetti from Castle's jacket and Castle says, "It's, uh, Australian money". Australian paper currency is almost psychedelic in the brightness of its colors. Red is for $20 bills.
The storyline of Ryan and Esposito fighting and going to couples counseling mirrors reports of Stana Katic and Nathan Fillion not getting along on set. They were even sent to couples counseling.
A major subplot of the story is Castle and Beckett celebrating their one-year wedding anniversary. Had the episode aired just a week earlier, it would have been closer in air date to the previous season's The Time of Our Lives (2014), the one where they get married.
Brynn Thayer was on One Life to Live with a young Nathan.