Dan finds himself between two girls when his childhood friend, Vanessa, returns to N.Y. and declares her feelings for him, just as he and Serena are trying to figure out what they mean to each other. At the masked ball, Blair sends Nate on a scavenger hunt, but Nate is distracted by his feelings for Serena. Although Blair said that outsiders were not welcome to the party, a disguised Jenny and Dan sneak into the ball. Finally, Lily asks Rufus to accompany her to an Eleanor Waldorf event only to make Bart Bass jealous.

Dan invites Serena and her family to spend the holiday with his family, creating an uncomfortable situation for Rufus and Lily. The children are unaware of their complicated romantic past. Meanwhile, Blair's freaks out when she learns that her father isn't coming home for Thanksgiving. Nate spends the holiday with his family, but their awkward dinner quickly goes from bad to worse.

Blair's father, Harold, comes home for the holidays with an unexpected guest. Blair cannot hide her disappointment and makes a plan to get rid of Roman forever. Jenny and Vanessa help Serena get the best Christmas present ever for Dan, who has a surprise of his own for Serena. Rufus refuses to remain the understanding husband any longer after Alison's former lover sends a letter to the house.

In the midst of Fashion Week, a furious Blair learns that her mother, Eleanor, at the suggestion of her protege Jenny, has given Serena and her new socialite friend, Poppy Lifton, front row seats to the Eleanor Waldorf show. Hurt once again by Serena's popularity and her mother's betrayal, Blair decides to sabotage the show. Meanwhile, Dan starts hanging out with Chuck, but a walk on the dark side always has its risks and Dan learns that the hard way. Lily learns a secret that her new husband, Bart, has been keeping from her.

Blair sets out on a mission to break up her mother and Cyrus Rose, her new man. Jenny moves in with Agnes as the two continue with their plans for their own fashion line. As Serena continues to fall for Aaron, she learns something that may derail their relationship forever while Dan interviews Bart Bass for an article for New York Magazine.

The Constance Billard and St. Jude seniors have the production of "The Age of Innocence". Serena has a crush on the play's director, Julian, and enlists Vanessa's knowledge of theater to help her get the guy's attention. Blair receives bad news about her future that leads her on a witch hunt for the person responsible. Dan and Rachel agree to stay away from each other in the aftermath of being discovered as more than teacher and student, but find it impossible to keep that promise. Chuck find help on an unlikely friend, Carter Baizen.

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.

As Lily awaits the consequences of her decision, William van der Woodsen, CeCe and Lily’s sister, Carol, come into town to support her and be part of a Taschen photo shoot on “modern royalty” in which the Rhodes family is participating. Unbeknownst to Carol, who has always chosen to keep her daughter Charlie far away from the Upper East Side, Charlie has followed her to New York to meet Serena and the rest of the family. Blair has an epiphany about her future, and grapples with the knowledge of whom she’s destined to be with.

Serena and Dan realize that they need to make amends with the people they have wronged. Chuck’s search for evidence of his father’s illegal activities leads him to a showdown with Bart.