
When Serena (Blake Lively) notices that Dan (Penn Badgley) has been cozying up to the new girl in school, Amanda (guest star Laura-Leigh), the ever-loyal Blair (Leighton Meester) and her minions decide to befriend Amanda and sabotage her budding new romance with "lonely boy."
The new episode of Gossip Girl (The Ex-Files) airs Monday @ 8/9 c on The CW.