"The Wrong Goodbye"
Georgina Sparks (guest star Michelle Trachtenberg) and former Constance mean girls Kati and Isobel (guest stars Nan Zhang and Nicole Fiscella) return for the season finale with another agenda. Blair must make a choice between Chuck and Prince Louis. "Gossip Girl" author Cecily von Ziegesar will also make a cameo.
Title comes from the 1973 film The Long Goodbye.
