Serena slips up at her new job in Hollywood. Chuck and Nate arrive in Los Angeles and meet up with Serena for a glamorous party. Plans for their wedding come between Louis and Blair. Dan has a problem when a magazine plans to print an excerpt of his book.

Nate reconnects with Diana. Serena urges Charlie to make a difficult decision about her future. Dan asks Chuck to help him stop his book from being published, but finds that Chuck is also in need of help. Blaire's future sister-in-law comes to town to visit.

Nate must decide whether to cross moral lines at Diana’s request. Chuck helps Dan come to terms with his fate, just as Dan continues to try to help Chuck break through his emotional block. Serena and Charlie return to the Upper East Side from California.

Dan decides to share the truth about his book with Serena, Blair, Nate, Chuck, Rufus and Lily. Blair and Louis hit a crises point after Louis reads Dan's book. Diana learns incriminating information about one of Nate's friends.

Blair and Louis find themselves in conflict with his parents during Yom Kippur. Serena's boss forces her to choose between Dan and her new job. Diana prepares to debut the New York Spectator and expects Nate to do whatever it takes to save the day when problems arise.

Blair holds a competition for the coveted bridesmaid spots in her upcoming royal wedding. Nate gets help from Charlie to make Diana jealous. Serena has to set aside her feelings about Dan so she can secure the film rights to Dan's book.

The group attends a provocative theatrical performance and it leads to surprising romantic twists. Diana sets her sights on Serena in her quest to destroy Gossip Girl. Dan's book tour isn't exactly what it seems to his friends.

Serena is hard at work planning a dream bridal shower for Blair. Chuck and Dan, upset at not being invited, spend the day together. Nate and Serena find a hidden weapon for Diana's quest against Gossip Girl.

Lily, Charlie and Serena eagerly anticipate the Studio 54 party being thrown in CeCe’s honor. Nate takes on a new role at the Spectator. Blair turns to an unlikely person for help.

Lily throws Charlie a party to officially introduce her to New York society. Charlie’s ex interferes with her future as an Upper East Side princess. Dan decides it may be time to tell Blair the truth about his feelings for her.

Blair's flashbacks reveal the fallout of her and Chuck's car accident, which Nate realizes may have been caused by foul play. Meanwhile, Lily gets a private eye to locate Charlie.

Blair prepares to celebrate her upcoming royal wedding with a bachelorette party. Nate joins forces with a surprising ally. Serena and Dan try to protect someone close to them.

Chuck wrestles with the reality that Blair is about to walk down the aisle with Prince Louis. Georgina's return threatens to throw the royal event into chaos.

Blair must make a difficult decision, the consequences of which could hurt those she loves most. Serena takes the blame for an incident with Gossip Girl in order to protect a loved one. Georgina, sensing a scandal, digs deeper.

It’s Valentine’s Day and Blair can’t resist playing cupid for someone she loves. Georgina is intent on stirring up more drama and decides to crash Nate’s Valentine’s Day party. Serena is shocked by something she witnesses at the party.

Dan feels honored when Upright Citizen’s Brigade is performing excerpts from his book. Blair tries to prove Serena’s suspicions wrong in order to save their friendship.

Blair thinks Cyrus may have found a potential loophole in her prenup. Chuck and Georgina partner up in a scheme. A family crisis brings William van der Woodsen back to NYC.

Chuck invites Jack to town as a thank you, but the trip doesn’t go exactly as planned. Blair and Dan's burgeoning romance hits a speed bump. Ivy finds an unlikely ally in William.

Serena tries to make a reluctant Lola the next “It Girl” of the Upper East Side. Chuck reaches out to Blair for advice about his past. Diana Payne’s return to The Spectator starts a power struggle with Nate.

To celebrate their official couple-hood, Blair and Dan host a glamorous British-themed Salon. Lola lands the audition of a lifetime. Serena and Diana face-off over secrets they both would prefer remain secrets.

Blair comes up with a plan to keep her Upper East Side status intact. Lily throws a family gathering. Nate digs into Diana’s past and is surprised by what he discovers.

Chuck, Nate, Blair, Serena and Lola team up to uncover what they think is an explosive secret between Diana and Jack. Meanwhile, Dan is offered a prestigious fellowship in Rome for the summer.

Blair enlists Serena to be her stand-in at an important meeting. Ivy and Lola team up to help Chuck with a personal vendetta/ Nate makes a decision about the future and Diana Payne.

When Gossip Girl attacks Blair, Serena admits she may be to blame. Nate invites Lola to move in with him. Lily must make a big decision about the future of her marriage.