On her first day at Columbia, Blair attempts to gain membership into an ultra-exclusive social club, Hamilton House .... but she’s in for a few big surprises. Serena begins to suspect that Juliet is intentionally sabotaging Serena’s life and that it may have something to do with Nate. Rufus is worried about Dan and decides to take matters into his own hands.

An anonymous Gossip Girl blast starts a very damaging rumor about one of Columbia's new students, Serena. On her path to greatness, Blair decides to take a class with a powerful businesswoman, Martha, who is guest-lecturing at Columbia, but a mysterious fellow student thwarts her plans to secure the prized position as Martha's assistant.

Although Blair made it perfectly clear that Little J was no longer welcome in Manhattan after what happened with Chuck, Jenny is tempted by a once-in-a-lifetime opportunity to meet Tim Gunn, which could be a game changer for her future. Meanwhile, Serena discovers something about her new boyfriend, Colin, that may put an end to their relationship just as it was getting good.

Blair is caught off-guard – and not in a good way – by a surprise guest at her birthday party. Having had enough of Chuck and Blair’s games, Serena and Nate decide to plan an intervention.

Chuck, Serena, Blair, Dan, Jenny and Eric find themselves faced with a crisis when a member of one of their families is hospitalized. Meanwhile, Nate attempts to help his parents, The Captain and Anne, put their complicated past behind them and reconcile.

Blair and Dan join forces to find Juliet. Serena expounds her boarding school experiences to her therapist and discovers the truth behind Juliet's vendetta against her. Meanwhile Chuck suspects Lily has not told him the full truth.

A former associate of Chuck’s father, Russell Thorpe – along with his daughter Raina – returns to Manhattan with some unfinished business for our Upper East Siders. Serena and Chuck join forces against Lily. Blair realizes that her mother, Eleanor, may be her key to becoming a future CEO. Nate worries that his father, The Captain, is having a little too much fun and not taking his parole seriously.

Blair is ecstatic to land an internship at W Magazine, but the thrill quickly fades when she finds out that Dan has secured one of the coveted positions as well. Chuck may have finally met his match with Russell Thorpe – and his daughter Raina – back on the Upper East Side. Nate receives alarming news about his father’s business prospects.

Blair enlists Nate’s help to win over her high-strung boss, Epperly, at W Magazine. Damien stirs up more drama on the Upper East Side. Chuck finds himself torn between business and pleasure. Florence and the Machine performs an acoustic version of “Cosmic Love.”

With Russell Thorpe poised for a takeover attempt of Bass Industries, Chuck makes one last-ditch effort to save his family’s company. Blair is given a challenging assignment at W Magazine with the promise of a possible promotion. Serena struggles with her feelings for Ben.

It wouldn’t be a proper Upper East Side party without some major Gossip Girl drama, and for Eric’s 18th birthday celebration there is plenty to go around. Blair decides to speed up the time table on her career path to becoming a powerful woman.... but ultimately stretches herself too thin. Serena is forced to choose between her family and Ben. Chuck and Lily’s relationship remains icy in the aftermath of Lily’s betrayal.

Ben’s mother comes to town, forcing issues to the surface between Ben and Serena. Russell Thorpe is determined to destroy Chuck’s family legacy, but he risks alienating his daughter, Raina, in the process. Billy Baldwin returns as William van der Woodsen, Lily’s ex-husband and Serena and Eric’s father.