Gossip Girl, Season ‪1‬

The privileged prep school teens on Manhattan's Upper East Side first learn that Serena van der Woodsen (Blake Lively, "The Sisterhood of the Traveling Pants") is back in town the way they learn all the important news in their lives -- from the blog of the all-knowing albeit ultra-secretive Gossip Girl. No one knows Gossip Girl's identity, but everyone in this exclusive and complicated vicious circle relies on her website and text messages for the latest scoop. Even Serena's closest friend, Blair Waldorf (Leighton Meester, "Entourage"), is surprised to find that Serena has suddenly ended her self-imposed exile to boarding school and returned to Manhattan. Once the Upper East Side's most notorious party girl, Serena's reasons for returning are mysterious, although they may have something to do with her younger brother Eric (Connor Paolo, "Alexander"). Whatever the reasons, the change in Serena is obvious, especially to Blair, whose friendship with Serena has always been competitive and difficult.

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. 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.

Ivy week equals drama 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 uncovers 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. Ed Westwick also stars.

Blair is thrilled when her mother 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.

Dan makes elaborate plans to impress Serena on their first official date. On the same night, Jenny is invited to the infamous Blair Waldorf sleepover and finds herself in a high-stakes game of Truth or Dare.

Dan is torn between two girls when his childhood friend, Vanessa (recurring guest star Jessica Szohr), returns home and declares her feelings for him, just as he and Serena are trying to figure out what they mean to each other.

After surviving their relationship's on-again/off-again genesis, Serena and Dan finally acknowledge that they are crazy about each other, despite their polar-opposite worlds that constantly threaten to pull them apart.

Devastated by the state of her relationship with Nate and still dealing with the guilt from a recent indiscretion, Blair puts on a happy face for her 17th birthday party and attempts to hide the truth from her friends.

When Dan finds out that Serena and her family are celebrating Thanksgiving alone, he naïvely invites them to spend the holiday with his family, creating an uncomfortable situation for Rufus and Lily.

Serena has absolutely no intention of attending the upcoming Debutante Ball, until her grandmother, CeCe (guest star Caroline Lagerfelt - "All the King's Men," "Nash Bridges"), announces that Serena must attend.

When Blair’s father, Harold (recurring guest star John Shea, comes home for the holidays with an unexpected guest -- his boyfriend, Roman (guest star William Abadie - "Entourage," "The O.C.," "The Pink Panther") -- Blair finds it difficult to hide her disappointment and hatches a plan to get rid of Roman for good.

The gang breaks into the school swimming pool for an impromptu night of fun, but when a member of their group nearly drowns, the school threatens to expel the person responsible for the break-in.

Gossip Girl takes pleasure in reporting that Serena van der Woodsen has been spotted buying a pregnancy test, and the word spreads like wildfire.

Blair returns to school after losing Queen Bee status; Serena's not fond of living with her future stepbrother, Chuck; and Jenny does something illegal in her quest for popularity.

Serena's world is turned around when her former partner in crime, Georgina Sparks (Michelle Trachtenberg - "Buffy the Vampire Slayer"), returns to Manhattan to stir up trouble.

Georgina (recurring guest star MIchelle Trachtenberg) informs Serena that she is prepared to reveal damaging information from Serena's past, but no one is ready 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 (recurring guest star Jesse Swenson), cheating on her, 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. Plus, one of the Upper East Side teens reveals that he is gay.

Georgina (recurring guest star Michelle Trachtenberg) reveals the true reason that Serena fled Manhattan for boarding school, and Serena quickly falls back into her old habits. 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 to assume the worst about his girlfriend. Meanwhile, Rufus is thrilled when his band is invited to perform at a Rolling Stone-sponsored concert, but Lily is the last person he expects to see at the performance, especially since her wedding rehearsal dinner is the same night. Recording artist Lisa Loeb and famous cake designer Sylvia Weinstock appear as themselves.

With Serena's life and reputation on the line, Blair -- as Serena's best friend -- decides to take matters into her own hands to deal with the manipulative and evil Georgina Sparks (recurring guest star Michelle Trachtenberg). Lily prepares for her wedding day, which is destined to be the Upper East Side's social event of the year, and finds that Rufus is never far from her thoughts. Serena finally opens up to Dan, pours out her heart and tells him the truth about her past, but will it prove to be too late to save their relationship? And Lily's interior decorator, Amelia (heiress and model Lydia Hearst), makes a big impression on Chuck.