Jenny yoinks the SIM card from her phone, which allows the girls to receive all of Serena’s incoming calls and texts and reply to them as if they were Serena.
Then they sew seeds of distrust in Dan and Nate by telling each that Serena will meet him in a predetermined location, making both think they got stood up.
Jenny manages to convince Lily that she should meet with Juliet, who drops the bomb about boarding school, at which point Lily writes her a check.
When Serena finds out about the check, she and Lily get into an old-fashioned blowout fight.
Meanwhile, Blair is in talks with Nate’s mom to be the “face” of a charity, Girls Inc. Vanessa gives Mrs. Archibald a copy of Serena’s resume, claiming S also wants the position.
Blair and Chuck are still sleeping together but claiming that they’re not in a real relationship.
His assistant says having a girlfriend would be bad for his bad-boy image, while Mrs. Archibald has told Blair that Chuck is in turn bad for her image as a strong woman.
Even so, they can’t stay away from each other. Chuck even accidentally tells Blair that he loves her in the heat of passion.
At the masked ball at the Empire, Juliet sneaks in by giving Serena’s name at the door, then wears a mask and poses as her.
She kisses both Dan and Nate before slinking away, then drops the curtain that shields Chuck and Blair, who are kissing.
Chair has just confessed its feelings to one another, though, and they don't care who sees.
Once the real Serena enters the party, Dan and Nate both confront her about kissing them and don’t believe her when she says someone was impersonating her.
Blair’s also mad, since she thinks S was trying to poach her spot at Mrs. Archibald’s charity. S
Blair then decides, after Anne tells her to hit the bricks, that they can’t date again after all. She wants to achieve things on her own, not be Chuck Bass’ girlfriend.
Chuck, somehow, understands and seems at peace with this.
Juliet somehow gets Serena wasted to the point where she's stumbling and can barely stand up. Juliet appears and bundles Serena into a cab, then climbs in with her.
She uses Serena’s SIM card to text the dean of Columbia that she's dropping out. Juliet drags her home to her apartment where God only knows what will happen now.
(Source: TV Fanatic)