Blair takes matters into her own hands to help Serena with the manipulative and evil Georgina Sparks. 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 they try to work things but it might be too late?
An unexpected guest shows up at Lily and Bart's wedding. Georgina goes somewhere where she can do no harm. Blair plans to go somewhere with Chuck.