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 text messages for the latest scoop. Serena's closest friend, Blair (Leighton Meester, "Surface"), is just as surprised as everyone else to find that Serena has suddenly ended her self-imposed exile to boarding school and returned to Manhattan. The tension between Blair and Serena isn't lost on Gossip Girl, who is determined to uncover and fuel any and all scandals. Does it involve Serena's brother Eric (Connor Paolo, "One Life to Live"), Blair's boyfriend Nate (Chace Crawford, "The Covenant") or Nate's buddy Chuck (Ed Westwick, "Children of Men"). Maybe it has something to do with Dan and his sister Jenny, whose middle-class background keeps them on the fringes of this exclusive clique. Even the parents from Serena's mother Lily, a former ballerina/rock-groupie, to Nate's high-powered father Howie "The Captain" Archibald, to Dan and Jenny's dad Rufus, a former rocker turned art gallery owner are aware that their sons and daughters are constantly checking their Sidekicks to read Gossip Girl's latest sightings and overheard tidbits. Overriding all the shifting friendships, jealousies and turmoil in this wealthy and complex world, the central mystery remains - Who Is Gossip Girl?