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.

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.

Blair comes up with a devious plan to take down her new teacher, Rachel. Chuck has no recollection of what happened to him when he wakes up in a hotel. Nate and Vanessa try to help Chuck fill in the missing pieces of his night. Meanwhile Dan and Serena try to keep their relationship together as Rufus and Lily grow even closer.

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.