The entire Upper East Side of Manhattan is rocked when Bart Bass dies suddenly in a limo accident. Serena and Eric take the news very calmly while Lily has a troubling time despite her mother, Cece's, awkward attempts to comfort her. Chuck begins to blame Lily for his father's death and threatens to reveal a secret that Bart found on her before his accident. Meanwhile, Blair's mother, Eleanor, prepares for her latest marriage to Aaron's father Cyrus.

In need of publicity for his new hotel, Chuck decides to move up his club’s opening and enlists Serena’s help to get the word out to her celebrity clients. Feeling left out of the planning, Blair attempts to win Chuck’s approval by secretly helping him with a problem concerning opening night. Dan is unnerved when he finally watches one of Olivia’s infamous sex scenes with co-star and real-life boyfriend at the time, Patrick Robinson. Jenny is forced to choose between her relationship with Eric and her new role as Queen Bee. Rufus gets Lily into the Halloween spirit.

Chuck finds himself once again at odds with his uncle, Jack Bass. Eleanor puts Blair in charge of making sure her latest fashion show is a huge success with an important client. Rufus attempts to get Jenny back on track by volunteering to have her help with Eleanor’s fashion show, but the opportunity takes a big turn for the worse when Jenny learns that Agnes will be one of the models.

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.

Blair and Dan join forces to find Juliet. Serena expounds her boarding school experiences to her therapist and discovers the truth behind Juliet's vendetta against her. Meanwhile Chuck suspects Lily has not told him the full truth.

In the midst of celebrating Yom Kippur with family and friends, Blair and Louis find themselves in a power struggle with Louis' family. Serena's boss puts Serena in the awkward position of choosing between her new job and her relationship with Dan. Diana prepares to debut the New York Spectator, but an unfortunate last-minute surprise delays the launch and Diana expects Nate to do whatever it takes to save the day.

Chuck invites Jack to town to thank him for saving his life, but finds the trip doesn’t go exactly as planned. Blair and Dan attempt to consummate their new relationship -- but unexpected roadblocks get in their way. Meanwhile, Ivy finds an unlikely ally in William in her quest to be accepted on the Upper East Side, and Nate is hopeful a new investor will save his newspaper.

Trying to prove herself in adult society, Serena hosts the Central Park Conservancy’s big gala, of which she is now the newest Board Member, and she and Nate both learn something shocking about their significant others. Blair prepares to debut her new fashion line, but a rival from her past holds the key to her future. With the help of Georgina, Dan lands some meetings with publishers, but he must decide if he is willing to sacrifice his integrity in order to get his work published. Meanwhile, Chuck tries to persuade Amira to help him look into his father’s past, even if it means jeopardizing Lily and Bart’s relationship.