S1, E17: Georgina (recurring guest star MICHELLE TRACHTENBERG) reveals the true reason that Serena fled Manhattan for boarding school, and Serena quickly falls back into her old habits. Blair, Nate and Chuck must put their complicated feelings for each other aside to help their friend. Unfortunately, Serena is too ashamed to share the truth with Dan, leaving him to assume the worst about his girlfriend. Meanwhile, Rufus is thrilled when his band is invited to perform at a Rolling Stone-sponsored concert, but Lily is the last person he expects to see at the performance, especially since her wedding rehearsal dinner is the same night. Recording artist LISA LOEB and famous cake designer SYLVIA WEINSTOCK appear as themselves.