After Felicity thinks she spots Blair kissing someone other than Elena, she decides to blow the whistle on him - until she realizes the mystery vixen is Elena's best friend. Meanwhile, Julie learns the identity of her birth mother.
Quest roles:
Ivana Milicevic, Rob Benedict, Elya Baskin, Janeane Garofalo(Sally Reardon (voice) (uncredited)), Boris Lee Krutonog(Yuri), Donal Logue(Eddie), Tammy Townsend(Tara Owens), Jane Kaczmarek(Carol Anderson), Ian Busch(Receptionist), Susan Dalian(Tina), Zorab Ovsepyan(Dimitri), Alex Stemkovsky(Leonid)