"The Backup Dan" begins with Blair and Dan successfully fleeing all the way to the airport to make their escape from New York. Elsewhere on the Upper East Side, Georgia has discovered some scandalous gossip and her newly revealed nature means she will not be letting it get away from her.moreless
As Blair prepares to walk down the aisle, Chuck tries to come to grips with losing the love of his life. Michelle Trachtenberg returns as Georgina to cause trouble, plus other surprises in the 100th episode.moreless
Blair confides in Serena about what happened after her car accident with Chuck. Meanwhile, Nate investigates possible foul-play causing the accident. Lily hires a private detective to track down Charlie. And Blair gets a wedding-dress fitting by Vera Wang herself!moreless
While Lily throws a coming out to society party for Charlie, Serena and Dan try to amend their friendship. It is now time for Blair to choose between Louis and Chuck, she receives help from Dan who has an agenda of his own. Max still tries to leak Charlie's story and at the end of the night she slips Gossip Girl information that could turn deadly.moreless
In the celebration of Yom Kippur with family and friends, Blair and Louis have a power struggle with Louis's family. Serena's boss asks her to choose between her new job and Dan. Diana prepares to debut the New York Spectator, but a surprise delays the launch and Diana expects Nate to help her.moreless
After much thought, Dan finally decides to gather everyone and reveal the truth about his book, hoping that they will support him at his book party. Meanwhile, Blair and Louis struggle after Louis reads Dan's book. Diana has some incriminating information about one of Nate's friends and uses it to her advantage.moreless
Nate has to decide whether to cross moral lines at Diana's request. Dan is trying to figure out who is publishing his book, and seeks help to stop it but ends up in the spotlight anyway. Chuck helps Dan and Dan helps Chuck break through. Meanwhile, Serena and Charlie return to the Upper East Side.moreless
Nate reconnects with Diana, who offers him an exciting opportunity. Serena forces Charlie to make a choice between worlds. Dan seeks out Chuck's help to stop the publication of his book, but discovers that Chuck is the one who needs help. Blair's future sister-in-law, Beatrice, arrives from Monaco, but her motives with Blair may be more than just to getacquainted.moreless
Serena loves her new job in Hollywood, but makes a mistake trying to impress her boss. Chuck and Nate arrive in LA as their last stop of their Lost Summer trip, joining Serena at a glamorous party, where Nate meets a sexy older woman. Blair and Louis return from Monaco and begin planning their royal wedding, but when Louis refuse to support Blair's decisions against his family, their relation is at risk. A magazine is planning to run an excerpt of Dan's book until an unlikely ally helps him.moreless
In the season four finale, will Blair choose her prince or her dark night?
The finale includes the return of Georgina and Constance Billard mean girls Kati and Is, a cameo by "Gossip Girl" author Cecily von Ziegesar, a performance by Airborne Toxic Event and, oh yeah, a few very juicy cliffhangers.