Trivia: Throughout the episode, it's heavily implied, short of mentioned outright, that Castle is being considered to write a new James Bond novel. Stana Katic is actually a Bond girl, having had a small role as a Canadian intelligence officer in 'Quantum of Solace'.
Question: Before this episode, there was a Christmas episode "Secret Santa" and then there was "Significant Others" with Meredith showing up to take care of Alexis. In that episode, Beckett mentions choosing the movie Valentine's Day for a date night, causing her to lose a turn. In this episode, Castle and Beckett are celebrating their first Valentine's Day together. So, are they celebrating Valentine's Day twice? This wasn't too long after the Christmas episode and when Beckett made her movie choice, no snow was on the ground. Is this a mistake or is this really their first Valentine's Day together?