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.