Blair takes matters into her own hands to help Serena deal with the manipulative and evil Georgina Sparks who threatens to expose Serena's secret. Lily, while keeping Rufus in her mind, prepares for her wedding with Bart Bass that is designed to be the Upper East Side's social event of the year. Serena finally tells Dan the whole truth about her past and about Georgnia and they try to work things out. But Dan is guilt-ridden after having cheated on Serena with Georgina and wonders if it is already too late. An unexpected guest shows up at Lily and Bart's wedding. Also Blair manipulates matters so that Georgina goes "somewhere where she can do no harm". As the end of the school year approaches, Blair plans to go somewhere with Chuck.

Welcome to New York's Upper East side where the wealthy and connected mingle at benefits and try to deal with their always dramatic love lives, not to mention picking colleges. Blair Waldorf is the so-called toast of adolescence in her world; she and her friends, Kati Farkas and Isabel Coates, go to a prep school and fancy parties with their rich parents. Blair is envied by her adversaries because she is thought to have the perfect life, not just because of her gorgeous boyfriend, Nate Archibald, but because she's also planning on getting into her dream college,Yale. With everyone worried about college(or procrastinating on worrying, which everyone seems to be doing), and senior year dragging along, her seemingly perfect life is interrupted by her ex-best friend, the beautiful Serena van der Woodsen, coming back into town after getting kicked out of boarding school. Serena comes back into her life, and into the eyes of Blair's boy friend. When everything Blair knows starts to fall apart, everyone will realize that her life is far from perfect. Will life in the the Upper East Side redeem itself of what it's really supposed to be? Or will the false facade reveal that the rich have the same problems as the not so rich (Jenny and Dan Humphrey), if not more. And just maybe Jenny and Dan are all the more happy with their simple, not so expectant lives