Trying to prove herself in adult society, Serena (Blake Lively) hosts the Central Park Conservancy’s big gala, of which she is now the newest Board Member, and she and Nate (Chace Crawford) both learn something shocking about their significant others. Blair prepares (Leighton Meester) to debut her new fashion line, but a rival from her past holds the key to her future. With the help of Georgina (guest star Michelle Trachtenberg), Dan (Penn Badgley) lands some meetings with publishers, but he must decide if he is willing to sacrifice his integrity in order to get his work published. Meanwhile, Chuck (Ed Westwick) tries to persuade Amira (guest star Andrea Gabriel, “Lost”) to help him look into his father’s past, even if it means jeopardizing Lily (Kelly Rutherford) and Bart’s (guest star Robert John Burke) relationship. Matthew Settle and Kaylee DeFer also star. Barry Watson and Sofia Black-D’Elia guest star.