While checking the motives of possible suspects, Beckett and Castle pay a visit to the captain of the oil tanker who survived the blast. Capt. Pike is covered with burn scars and confined to a wheel chair. Clearly, an homage to Capt. Christopher Pike from Star Trek T.O.S.
This episode aired the day after Stana Katic's 31st birthday. Beckett wouldn't be acknowledged as being 31 until "Rise (2011)".
When Castle challenges Beckett to a final cards showdown, he says "mano a mujere." Beckett calls him on it as the wrong expression "hand to woman." She is correct. The correct expression would have been "hombre a mujere."