Gossip Girl - Season 1 - Eps 15: Desperately Seeking Serena
Serena's world descends into chaos when a former friend, the evil Georgina Sparks returns to town. Nate connects with the last person he expected, Vanessa. Blair hatches a plan to sabotage her biggest rival, Nelly Yuki. Meanwhile Serena goes out with Georgina, but things get so bad that Serena thinks someone spiked her non-alcoholic drink. Jenny develops a crush on a dog-walker, Asher Hornsby, who might be her ticket to permanent popularity.
About Gossip Girl

Title: Gossip Girl
First Air Date: 2007-09-19
Last Air Date: 2012-12-17
Status: Ended
Rating: 8.202/10 (from 2159 votes)
Language: EN
Seasons: 7
Total Episodes: 121
Network: The CW
Genres: Drama, Mystery
Production Companies: Warner Bros. Television, Alloy Entertainment, Fake Empire Productions, CBS Studios
Synopsis
An exclusive group of privileged teens from a posh prep school on Manhattan's Upper East Side whose lives revolve around the blog of the all-knowing albeit ultra-secretive Gossip Girl.
Cast

Blake Lively
Serena van der Woodsen

Leighton Meester
Blair Waldorf

Penn Badgley
Dan Humphrey

Chace Crawford
Nate Archibald

Ed Westwick
Chuck Bass

Kaylee DeFer
Ivy Dickens

Kelly Rutherford
Lily van der Woodsen

Matthew Settle
Rufus Humphrey