Blair gets excited when her mother, Eleanor, chooses her to be the new face of her clothing line. However, Blair's happiness turns quickly into feelings of betrayal and jealousy when Serena takes her spotlight and Blair finds herself back in Serena's shadow. Meanwhile, Serena and Dan remember once again that they come from two very different worlds. Also, Nate and Chuck do a boys weekend to blow off steam after Ivy Week ends.

Blair is feeling heartbroken and guilty by the current state of her relationship with Nate and her recent indiscretion. But she manages to put on a happy face for her 17th birthday party and attempts to hide her feelings from her friends. Hoping that Serena and Vanessa can bond, Dan takes Vanessa to Blair's birthday party. Jenny brings her mother home as a surprise, but Rufus isn't ready to forgive and forget. Finally, Nate's parents ask him to make a huge sacrifice to save his father's business.

Serena's grandmother announces that Serena has to go to Debutante Ball. However, Dan is not what CeCe wants as an escort for Serena, and she makes her opinion heard loud and clear, causing a rift between Serena and Dan. Although they are officially broken up, Nate asks Blair to go to the ball with him. A jealous Nate begins to suspect that Blair is seeing someone else. Jenny finds herself having to make the decision of either attending her mother's art opening or following her dreams to the Debutante Ball, even though her parents don't want her to go.

After Georgina reveals the true reason Serena left Manhattan, Serena goes back into her old habits. Her friends Blair, Nate, and Chuck, in order to help her, have to put their differences aside. Meanwhile, Rufus is excited when his band is invited to perform at a Rolling Stone-sponsored concert, but Lily is the last person on earth he expects to see at the performance, especially since her wedding rehearsal dinner is the same night.

As the summer draws to a close in the Hamptons, Serena and Nate have everyone fooled into thinking they are a couple to cover up the fact that Nate has been hooking up with a married, older woman. Blair returns from abroad with a hot guy on her arm, making a very jealous Chuck question his decision to leave Blair stranded at the heliport. Dan has spent the summer assisting a famous author. While interning for Eleanor Waldorf's company, Jenny sneaks an invite to a much-coveted Hamptons' White Party at which Eric introduces her to socialite Tinsley Mortimer.

After Blair and Serena get into a catfight, Serena decides to get even with Blair, who has always dreamed of attending Yale, by ditching her plans to visit Brown, and instead accepting the Dean of Yale's personal invitation to visit the school. After discovering that none of his recommendation letters for Yale were ever submitted, Dan frantically tries to figure out a way to salvage his chances of getting into the school. While on the Yale campus, Chuck is kidnapped by a group of Skull and Bones members and Nate hooks up with a co-ed.

It's Thanksgiving time and Blair is offended when her Mom's new man hijacks her Thanksgiving traditions. Lily attempts to strengthen the frail bond between Rufus and Jenny. Eric discovers a secret about Bart. Vanessa and Chuck help Nate deal with his father.

The students are stressed out as they find out who was accepted and who didn't make the cut for early admission to Yale. Meanwhile, Serena bonds with Rachel, her Shakespeare teacher, who is unaware of what Blair has in store for her following receiving her first B; Chuck finds an unlikely ally in his feud with Jack; and Nate and Vanessa have a romantic evening together.

Gossip Girl decides to liven things up at the Constance Billard and St. Jude’s graduation by sending out a shocking and damaging email blast in the midst of the commencement ceremony, stirring Serena to come up with a plan of attack. The Mean Girls challenge Jenny to throw her hat in the ring to succeed Blair as Queen Bee next year. Lily and Rufus struggle to repair their relationship after Lily’s betrayal. As for the cliffhangers, Blair and Chuck finally… and Serena is shocked by… and Georgina decides to… and Dan, Nate, and Vanessa unknowingly…. Jenny and Eric do something they might end up regretting.

As summer draws to an end, Blair and Chuck continue to adjust to being in a relationship with one another. Serena returns from Europe with new secrets to hide and a new relationship with Carter Baizen. Nate also returns from vacationing and brings home a mysterious girl, Bree Buckley. Meanwhile, Rufus, Dan and Jenny spend the summer in the Hamptons and learn to adjust to the van der Woodsen's glamorous lifestyle

It wouldn’t be Thanksgiving on the Upper East Side if there wasn’t a serving or two of some major drama for the holiday. Blair suspects her mom has been keeping a big secret from her, but it turns out to be something else entirely. Vanessa is supposed to spend Thanksgiving with her parents, but has a fight with her mom and shows up on Dan’s doorstep. Rufus learns that Lily has been lying to him about her mother, Cece. Chuck tells Nate that he has some potentially damaging information about one of their friends. Jenny learns that Eric was behind her very public embarrassment at Cotillion and can’t pass up a chance to get even. Serena is put in a very awkward position when her mother invites Trip and Maureen to join them for Thanksgiving dinner.

Blair must decide whether to meet Chuck at the top of the Empire State Building or risk losing their future together. A Gossip Girl gossip bomb involving Dan explodes Serena and Nate's relationship. Dorota and Vanya welcome their baby. Jenny hits rock bottom. Georgina returns to the Upper East Side...and she has an agenda.

Blair and Serena spent their summer living it up in the belly of the beast: Paris, France. But where there's Paris there's bound to be boutique, Balenciaga, and of course, boy trouble. Unaware of Chuck's shooting in Prague, Blair struggles to forget him; things take a turn, however, when Chuck mysteriously shows up in Paris with a foreign stunning blonde at his arm. Meanwhile Serena contemplates which of her long-time beaus could be the one for her: Dan or Nate? Even on the Upper East Side drama erupts as Dan figures out the baby mama drama with Georgina, and Nate realizes something about himself when he meets fellow Columbia student, the intriguing Juliet.

Living out a real-life fairytale in Paris, Blair is pursued by a handsome young man, Louis, who she suspects is a member of Monaco's royal family. A very concerned Lily asks Serena to help her find Chuck, who hasn't been heard from or seen in months. Meanwhile, Chuck Bass is as we've never seen him before, adjusting to a fresh start in Paris with a mysterious new woman, Eva, at his side. Juliet offers to help Nate win Serena back, suggesting that reigniting Dan and Vanessa's romance may just be the trick to remove Dan from the Dan-Serena-Nate love triangle.

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.

The episode continues from the early events of the Constance Alumni event. Georgina Sparks turns up at the event looking for trouble. Serena and Vanessa reluctantly join forces to find Dan and Charlie, who does not take Dan's rejection of her well. Blair must make a choice between the men in her life when her life is in danger by Russell.

Serena loves her new job in Hollywood, but makes a costly misstep when she tries to impress her boss. Chuck and Nate arrive in Los Angeles as the last stop of their Lost Summer trip, joining Serena at a glamorous Hollywood Hills party, where Nate meets a sexy older woman. Blair and Louis return from Monaco and begin planning their royal wedding, but when Louis refuses to stand up to his family and support Blair’s choices, his weakness threatens their relationship. A magazine is planning to run an excerpt of Dan’s book until an unlikely ally steps in to help him kill the story.

The much-anticipated 100th episode will open with a musical dream sequence featuring Serena, Blair and all the men in their lives. Also, while Chuck wrestles with the reality that Blair is about to walk down the aisle with Prince Louis, the return of Georgina Sparks might make the royal affair a royal disaster.