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 and Serena has been secretly mourning her break-up with Dan.
Blair is over the moon that she is dating royalty and has every intention of becoming a royal herself, but a scheming Chuck has other plans for Blair and hew new love, Marcus.
Serena and Dan are forced to deal with their unspoken problems while trapped in an elevator during a citywide blackout. In a humorous twist, Blair questions the lack of passion in her relationship with Marcus, while at the same time Chuck appears to have lost his "passion" for any woman other than Blair.
When Serena notices that Dan has been cozying up to the new girl in school, Amanda, the ever-loyal Blair and her minions decide to befriend Amanda and sabotage her budding new romance with "lonely boy." Vanessa discovers a scandalous secret about Catherine and enlists Blair's scheming expertise to use the information to help Nate. Meanwhile, Lily finds herself drawn back to her ex, Rufus, once again.
In the midst of Fashion Week, a furious Blair learns that her mother, Eleanor, at the suggestion of her protégé Jenny, has given Serena and her new socialite friend, Poppy Lifton, front row seats to the Eleanor Waldorf show.
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.
Vanessa uses the scandalous picture of Catherine and Marcus to blackmail Blair into being a nicer person, so Blair seeks revenge by enticing Chuck to seduce Vanessa. Lily and Bart throw an extravagant housewarming party and expect their children to make them proud in front of the attending press, but a rebellious Serena isn't ready to play by their rules. Meanwhile, Dan and Jenny discover a big secret that Nate has been keeping from his friends.
Jenny befriends a young model, Agnes who encourages Jenny to not only explore her wild side, but also confront her boss, Eleanor Waldorf, who is attempting to "borrow" Jenny's designs.
Serena invites Aaron to be her guest at a charity gala honoring Lily and Bart, but after discovering a secret that Aaron has been keeping from her she begins to question whether Aaron is the guy she thought he was.
Blair does not approve of the new man, Cyrus Rose, in her mother's life, so she makes it her mission to break up the lovebirds by any means necessary. Jenny moves in with Agnes as the friends move forward with their plans for a fashion line.
Thanksgiving in the Waldorf household finds Blair upset that her mom's new boyfriend, Cyrus, has decided to ruin all her favorite traditions, but that's nothing compared to what's coming next.
For the annual Snowflake Ball, Blair and Chuck make a bet that they can find the ideal dates for each other. Aaron's ex-girlfriend, Lexi, expresses an interest in Dan which creates conflicted feelings for Serena. Nate, Jenny and Vanessa get into a tangled situation that puts their friendships and hearts on the line.
A sudden and tragic event impacts the lives of our favorite Upper East Side teens and their parents.
With Chuck MIA since his father's funeral, Uncle Jack arrives on the Upper East Side to help Chuck pick up the messy pieces, but first he has to find him.
With the reading of Bart's will, Chuck, Bart's brother, Jack, and Lily learn the fate of the Bass Empire. Rufus and Lily's relationship is strained as Rufus seeks details about the child he never knew he had.
It’s that stressful time of year when Constance Billard and St. Judes students find out who is and isn’t worthy of early admission to Yale University. Serena bonds with her new Shakespeare teacher, Rachel, who has no clue the wrath she is about to suffer after giving Blair the first B of her prep school career. Chuck pairs up with an unlikely ally in his war with Jack over Bass Industries. Nate and Vanessa spend a romantic evening at the opera.
In retaliation for not playing by the unspoken rules of Constance Billard, Blair hatches a plan to bring down her teacher, Rachel, and it's going to be good. After Chuck wakes up in a hotel and only has a minor recollection of what happened the previous evening and who he spent the evening with, Nate and Vanessa try to help him fill in the missing pieces of what is turning out to be an increasingly intriguing mystery.
The Constance Billard and St. Jude seniors put on a production of "The Age of Innocence" and find their personal lives mirroring conflicts in the play.
Devastated by the recent plot twist in her life, Blair turns her back on her predictable Waldorf existence in favor of a more wild and unpredictable lifestyle, causing Serena and Chuck to have serious concerns about their friend.
Serena decides to throw Jenny an intimate party for her sixteenth birthday, but things get way out of control when Poppy Lifton turns the small gathering into a huge social event. In a moment of weakness, Vanessa agrees to help Chuck with a scheme having to do with Blair and Nate. Rufus earns that Dan will not receive financial aid at Yale and tries to figure out another way to cover the cost of his education.
Serena returns from her trip to Spain with Poppy and Gabriel. Blair makes a secret deal with Nate's grandfather, William and Nate learns some disturbing information about his father's arrest. Dan takes a job as a cater-waiter to earn money for college, but is distressed when he discovers the gig is a Passover Seder at the Waldorf penthouse and several of his friends and family are guests.
Georgina returns to the Upper East Side after undergoing a major transformation. Chuck and Nate find themselves at a major crossroads in their relationship as it pertains to their mutual interest in Blair. Serena finds her relationship with Gabriel growing more complicated.
Blair pressures Georgina into making amends for her past bad behavior by helping her in a scheme. The rivalry between Nate and Chuck over Blair comes to a head. Lily hatches a secret plan to help Rufus with Dan's college tuition.
In a flashback to the 80s, 17-year-old Lily Rhodes gets kicked out of boarding school and runs away to Los Angeles, reconnecting with her parents, Rick and Cece, and sister, Carol.
Gossip Girl shakes things up by sending out a damaging email blast during the commencement ceremony. Rufus and Lily try to repair their relationship.