Serena loves her new job in Hollywood, but makes a costly misstep when she tries to impress her boss. Chuck and Nate arrive in Los Angeles as the last stop of their Lost Summer trip, joining Serena at a glamorous Hollywood Hills party, where Nate meets a sexy older woman. Blair and Louis return from Monaco and begin planning their royal wedding, but when Louis refuses to stand up to his family and support Blair’s choices, his weakness threatens their relationship. A magazine is planning to run an excerpt of Dan’s book until an unlikely ally steps in to help him kill the story.

Nate reconnects unexpectedly with Diana, who offers him an exciting opportunity. Serena forces Charlie to decide which world she wants to embrace. Dan seeks out Chuck’s help to stop the publication of his book, but discovers it is Chuck who needs the help. Blair’s future sister-in-law, Beatrice, arrives from Monaco, but her motives with Blair may be more than just to get acquainted.

Nate must decide whether to cross moral lines at Diana’s request. Dan has figured out who is publishing his book, and seeks help to stop it, but he ends up in the spotlight anyway. 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.

After much deliberation, Dan decides to gather Serena, Blair, Nate, Chuck, Rufus and Lily to reveal the truth about his book in the hope that they will support him at his book party. Meanwhile, Blair and Louis hit a crises point after Louis reads Dan's book. Diana learns incriminating information about one of Nate's friends and uses it to her advantage.

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.

Blair makes all of her former minions and Charlie compete to secure the coveted bridesmaid spots in her upcoming royal wedding. Nate is tired of keeping his relationship with Diana a secret, so he decides to use Charlie to make Diana jealous. Serena's boss is determined to acquire the film rights to Dan's book, so Serena must put her personal feelings about Dan and the book aside in order to close the deal.

Several of our favorite Upper East Siders attend a performance of Punchdrunk’s provocative theater experience, “Sleep No More,” which translates to masks, anonymity and some surprising romantic twists by the end of the evening. Meanwhile, Diana sets her sights on Serena in her quest to ruin Gossip Girl. Dan is out on his book tour, but things aren’t exactly as they appear to his friends and family.

Serena is hard at work planning a dream bridal shower for Blair, but it should come as no surprise that Serena has to plant some false information about the shower in order to keep Blair from finding out all the details. Chuck and Dan decide to spend the day together to distract themselves from the fact that they didn’t make the invite list for Blair’s shower. Nate and Serena find a silver bullet in Diana’s war against Gossip Girl, but struggle about whether to use it or not.

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

Serena decides she is ready to relinquish the spotlight and sets out to make a reluctant Lola the next “It Girl” of the Upper East Side, starting with modeling at a Kiki de Montparnasse lingerie show. Meanwhile, Chuck reaches out to Blair or advice about his past, and Diana Payne’s return to The Spectator starts a power struggle with Nate.

To celebrate their official coming out as a couple, Blair and Dan host a glamorous British-themed Salon, including guests Julian Tepper and Jenna Gribbon Lola lands the audition of a lifetime, but Gossip Girl may have other plans for the Upper East Side’s latest It Girl. Meanwhile, Lily and Rufus disagree over the best way to handle the Ivy situation, and Serena and Diana face-off over secrets they both would prefer remain secrets.

Blair feels like her Upper East Side status might be slipping away and devises a plan to assure that doesn’t happen. Meanwhile, Lily throws a family gathering – including William, Carol and Lola – in an attempt to prove the van der Woodsen family is as united as ever. Finally, 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 when Blair finds herself needing to be in two places at the same time. Meanwhile, Ivy and Lola team up to help Chuck with a personal vendetta, and Nate makes a decision about the future with Diana Payne.