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.