1.15 "Desperately Seeking Serena"

Serena's world becomes chaos when a former friend-turned-enemy, the evil and sociopath Georgina Sparks, returns to town and transfers to her school. Dan sees Serena preoccupied and he assumes that it has something to do with the nasty Chuck, who's looking forward to making her life a living-hell as her soon-to-be step-brother. Nate connects with the last person he expected, Vanessa over his failed relationship with Blair. Serena goes out with Georgina for a night on the town to try to patch things up between them, but things get so bad that Serena thinks someone spiked her drink. Meanwhile, Hazel and Penelope try to recruit newcomer Nelly Yuki to be part of their gossip club, but it is not easy. Blair supervises the whole operation and hatches a plan to sabotage Nelly. When Nelly breaks down after being reminded of her recent break-up with her boyfriend, the ladies find their way in and Nelly comes to the Waldorf penthouse where Blair tries to repair the damage. Elsewhere, Jenny develops a crush on 16-year-old dog-walker, Asher Hornsby, who might be her ticket to permanent popularity.