Gossip Girl (season 1)

In the wake of the scandalous Kiss on the Lips party, Serena receives an ice-cold reception from her best friend Blair, who reveals that she knows Serena slept with her boyfriend, Nate, before mysteriously running off to boarding school. As if it could not get any chillier, Serena decides to take Dan to archenemy Chuck's fundraiser brunch at The Palace, and Jenny seeks advice from Blair, who realizes she may have something to gain by allowing Jenny into her inner circle.

As the Upper East Side teens from Constance Billard and St. Jude's prepare for a much-anticipated visit from the Ivy League representatives, Blair and Chuck uncover a scandalous secret about Serena that may not remain a secret much longer. Dan has his heart and future set on the coveted usher position for the Dartmouth rep, only to be beat out by Nate, who has no interest in the school despite pressure from his controlling father, The Captain. Meanwhile, Jenny bonds with Serena's younger brother, Eric, and Rufus must swallow his pride and ask Lily for a favor to help his son, Dan.

Blair is thrilled when her mother, Eleanor, chooses her to be the new face of her clothing line. However, Blair's happiness soon turns to feelings of betrayal and jealousy when Serena moves into the spotlight and Blair finds herself back in Serena's shadow. Meanwhile, Serena and Dan are reminded once again that they come from two very different worlds, and Nate and Chuck indulge in a boys' weekend to blow off steam after Ivy Week.

Absent: Taylor Momsen as Jenny Humphrey.

Dan makes elaborate plans to impress Serena on their first official date. The same night, Jenny is invited to the infamous Blair Waldorf sleepover and finds herself in a high-stakes game of "truth or dare". Meanwhile, when Lily discovers that Eric is missing from his treatment center, she finds herself seeking help from her ex-boyfriend, Rufus.

Absent: Ed Westwick as Chuck Bass and Chace Crawford as Nate Archibald.

Dan is torn between two girls when his childhood friend, Vanessa, returns home and declares her feelings for him, just as he and Serena are trying to figure out what they mean to each other. At the infamous masked ball, Blair sends Nate on a scavenger hunt, but Nate is ultimately still distracted by his feelings for Serena. Although Blair makes it perfectly clear that outsiders are not welcome, a disguised Jenny and Dan sneak into the ball. Finally, Lily asks Rufus to accompany her to an Eleanor Waldorf event in order to make Bart Bass jealous.

Note: This is Jessica Szohr's first appearance as Vanessa Abrams.

After surviving the on-again/off-again nature of their new relationship, Serena and Dan finally acknowledge they are crazy about each other, despite their polar opposite worlds that constantly threaten to pull them apart. Chuck contemplates investing in a burlesque club in the hopes of making his hard-to-please father, Bart, proud of him. Nate confronts his father, The Captain, about the drugs he found in the house, but his father denies having a problem. Jenny discovers a secret her father, Rufus, and mother, Alison, have been keeping from her. Serena and Dan sleep together for the first time. Finally, Blair is once again devastated by Nate's actions after Jenny reveals that Nate kissed her by accident thinking she was Serena. Blair has sex with Chuck, Nate's best friend.

Devastated by the current state of her relationship with Nate and still dealing with the guilt from her recent indiscretion, Blair puts on a happy face for her 17th birthday party and attempts to hide the truth from her friends. Hoping to ease the tension between Serena and Vanessa, Dan takes Vanessa to Blair's party so the girls can have some bonding time, but this only ends up making Serena more uncomfortable. Jenny brings her mother (Susan Misner) home for a surprise visit, but Rufus may not be ready to forgive and forget. Nate's parents (Sam Robards and Francie Swift) ask him to make a huge sacrifice in an effort to salvage his father's business as he faces charges of embezzlement and fraud.

When Dan hears that Serena and her family are spending Thanksgiving alone at The Palace, he naively invites them to spend the holiday with his family, creating an uncomfortable situation for Rufus and Lily whose children are unaware of their complicated romantic history. Meanwhile, Blair's emotions spiral out of control when she learns that her father is not coming home for Thanksgiving. It is hinted that Blair is bulimic. Nate spends the holiday with his mom and dad, but their awkward dinner quickly goes from bad to worse.

Absent: Ed Westwick as Chuck Bass.

Serena's plan on not attending the annual Cotillion Ball is sidetracked when her grandmother CeCe persuades her to attend; Nate sees Blair's new buoyant attitude and entrusts Chuck to find out the reason, in which Chuck tells Nate that she is having an affair with St. Jude's alumni, Carter Baizen (Sebastian Stan), creating drama at the Ball. Blair finds out Chuck did this for personal gain and ends their affair, returning to Nate once more and consummating her love to him during a passionate night. Meanwhile, Jenny attends the ball despite it being on the same night as Alison's art gallery opening.

When Blair's father, Harold, comes home for the holidays with an unexpected guest—his boyfriend, Roman (William Abadie). Blair finds it difficult to hide her disappointment and hatches a plan to get rid of Roman for good. Jenny and Vanessa help Serena plan the best Christmas surprise ever for Dan, who may have a surprise of his own in mind for Serena. Chuck texts Blair that Nate has joined him in Monaco, worrying Blair that Chuck may disclose the details of their hook-up. Rufus refuses to remain the understanding husband any longer after Alison's former lover calls the house. Serena creates a Winter Wonderland for Dan and he gives her a love letter, they sleep together again and go back to their families for Christmas morning.

Absent: Ed Westwick as Chuck Bass and Chace Crawford as Nate Archibald.

Serena, Blair, Nate, Chuck and their entourage break into the school swimming pool for a night of fun, but when a member of their group nearly drowns, the school threatens to expel the person responsible for the break-in. Everyone agrees to keep a secret pact and say nothing, but it ultimately creates major tension between Serena and Dan, who isn't sure he's ready to take the fall for someone else and risk his future. Vanessa is working on a documentary project about private schools and accidentally captures Blair and Chuck discussing their affair. Lily contemplates telling Rufus how she really feels about him.

Absent: Taylor Momsen as Jenny Humphrey.

Gossip Girl takes pleasure in reporting that Serena van der Woodsen was spotted buying pregnancy tests. Of course, on the Upper East Side, the truth is often even juicier and more scandalous than the gossip, and this time is no exception.

Having been recently dethroned as "Queen Bee", Blair hesitantly returns to school with the support of her BFF, Serena. Meanwhile, Serena struggles to adjust to her new living arrangements with her future step-brother, Chuck, while receiving disturbing packages from an unknown sender. Jenny needs something to wear to her birthday party and her drive to be popular hits an all-new time high when she does something illegal to fit in with her new Upper East Side friends.

Note: From this episode on, Szohr (Vanessa) is added to the main cast and is credited in the opening titles.

Serena's Upper East Side world is turned upside down when her former partner in all things bad, Georgina Sparks (Michelle Trachtenberg), returns to Manhattan to stir up trouble and Serena's past. When Dan notices that Serena seems preoccupied, he jumps to the conclusion that it must have something to do with Serena's new roomie and soon-to-be step-brother, Chuck. Nate finds romance with the last person he was expecting to connect with, Vanessa. Jenny meets a new guy, Asher Hornsby, who just might be her ticket to permanent popularity. Finally, Blair hatches a secret plan to sabotage her biggest rival, Nelly Yuki ().

Georgina informs Serena that she is prepared to reveal damaging information from Serena's past, but no one is prepared for what Georgina does next. Blair and Jenny escalate their "popularity war" by spreading scandalous rumors about each other through Gossip Girl. Dan witnesses Jenny's new boyfriend, Asher, cheating with another boy who we find out to be Eric, Serena's brother, but Jenny refuses to listen to her brother's warning. Rufus goes to Lily for advice on how to handle Jenny's recent out-of-character behavior.

Absent: Ed Westwick as Chuck Bass and Chace Crawford as Nate Archibald.

As a result of Georgina revealing the true reason that Serena fled Manhattan for boarding school, Serena falls back into her old habits and Blair, Nate and Chuck must put their complicated feelings for each other aside to help their friend. Unfortunately, Serena is too ashamed to share the truth with Dan, leaving him only to assume the worst about his girlfriend. Rufus is thrilled when his band is invited to perform at a Rolling Stone-sponsored concert, but Lily is the last person on earth he expects to see at the performance, especially since her wedding rehearsal dinner is the same night.

Absent: Taylor Momsen as Jenny Humphrey.

With her best friend Serena's life and reputation on the line, Blair decides to take matters into her own hands in dealing with the manipulative and evil Georgina Sparks. With Rufus never far from her thoughts, Lily prepares for her wedding day which is destined to be the Upper East Side's social event of the year. Serena finally pours out her heart and the truth about her past to Dan, but will it prove to be too late to save their relationship? And Chuck admits his feelings for Blair to Nate, allowing the two of them to mend their friendship. Heiress and model Lydia Hearst guest stars in the episode as Amelia, Lily's interior decorator.