In the pilot that sets up the overall story, Gossip Girl spreads the news that "it girl" Serena van der Woodsen (Blake Lively) has returned to the Big Apple after a mysterious and self-imposed exile to boarding school. Her return is stirring the social pot.
The show opens with Serena on a train back into the city. She arrives at Grand Central just as Dan and Jenny Humphrey also get off a train at the famous station. They spent the weekend visiting their mother, who is taking a time-out from her marriage. Dan eyes Serena longingly.
Over at the Waldorfs, there's a classy party going on. But word quickly spreads that Serena is back in town, as Isabel Coates, Katy Farkas and Chuck Bass - three former friends/classmates - express shock and wonder over why she's returned. Blair Waldorf, meanwhile? She reacts to the news by pulling boyfriend Nate Archibald into a room and saying she wants to lose her virginity right at that moment. But then - gasp! - a knock at the door. Blair's mother tells her that Serena is at the party.
When Nate sees here, there are obvious feelings on his part. When Blair sees here, there are also obvious feelings... of disgust. Serena quickly exits the apartment, however, and makes her way to a hospital. Turns out her brother is a patient there. Looks like he's attempted suicide - and while Serena spends the night there, caring for her sibling, it's apparent her mother is ashamed of the attempt. Her and Serena clash.
Meanwhile, we're taken to the Humphrey's kitchen, as dad whips up breakfast for Jenny and Dan. Jenny is excited because she gets an invite to the Kiss on the Lips party, as long as she addresses the invitation. We learn that this family isn't as well off as the others, but attend private school for the education.
Flash to Serena on the way home where she's cut off by Nate. He tries to talk to her, but Serena replies that she did not come back for him. He's taken. By her best friend. And she won't get in the way of that. There's a definite past of some sort between these two.
In the present, meanwhile, we then see a couple scenes that sum up the social ladder: Dan is ignored on the buss by Chuck and Nate, as they don't even know he goes to their school; also, Serena is blatantly uninvited to the Kiss on the Lips party by Blair, as she makes her feelings known - in front of Katy and Isabel and even Jenny, who feels lucky to just be there - that she is now the Queen Bee.
Later on, though, Serena meets up with Blair (at one of those bars in NYC that welcomes high school kids) and opens up to her: she's sorry she didn't tell her she was leaving for boarding school... she doesn't wish to mess up her newfound social status... she just wants them to be friends again. The speech seems to work, as Blair embraces Serena before running off to meet Nate. But Gossip Girl suspects that Serena (often referred to as "S") is hiding something.
And we soon learn what it is: Chuck finds Serena at the bar of the Palace Hotel (which his parents own) and he tries to sleep with her. As his (unsuccessful) act of seduction is going down, he tells Serena that he knows her secret, he knows why she left for boarding school - at a wedding last year, she and Nate had sex. Simultaneously, Nate is coming clean about this act of indiscretion to Blair... just before they were about to jump into bed together. Guess that means he's sort of a good guy. But Blair doesn't see it that way. She flips out, throws him out, and lets the tears flow.
Serena actually runs into Dan on the way out of the hotel and drops her cellphone. When Dan goes to return it to the hotel, Serena shows up... and uses Dan as an excuse to her mom to get out of the Kiss on the Lips party. Just like that, they set up a date to attend his father's band's concert that night.
In other dating news, Nate asks Blair to dinner. He starts to apologize, and she instantly accepts. Just like that, they're back together.
We also discover that Lily (Serena's mom) and Rufus (Dan's dad) once had a fling back in the day.
Finally, it's the Kiss on the Lips party. Chuck makes a move on the "newbie," Jenny. But our sweet, innocent girl turns down his advances. He persists and she texts Dan for help. He and Serena quickly make their way to the party, where they find Chuck all up on Jenny, against her will. Dan punches him out, Serena screams at Chuck and he yells back that her life is over because he "knows everything!"
We close with Dan, Jenny and Serena in a cab. And Gossip Girl comments on how heroic an exit Serena has made. Too bad for her, of course, there's school on Monday...
(Source: TV Fanatic)