Serena tells Dan that Aaron won't be accompanying her to the ball. Dan agrees to go with her instead. But not together. As friends. They're both gonna go solo.
Jenny asks Vanessa for help reorganizing Rufus's records. It's not only a friendly gesture, but J's attempt to avoid thinking about her career and Nate. V still has not mentioned the letter she stole on Thanksgiving.
She also has not mentioned her make-out sessions with Nate, although that does not remain a secret for long after one of Gossip Girl's minions spots them kissing on the street. Minutes later, Jenny sees it online.
Lily tells Rufus that she's been avoiding Bart, but Bart corners Lily on the street and tries to apologize for his deceitful ways. She says she's going to have to think it over before she forgives him.
A member of Blair's posse asks Jenny to design her a dress for the ball. J agrees, and the evil girls plant an idea in her head. After Isabel buys a see-through dress by mistake (you can only see it under the light, though), they convince J to make Vanessa a nice dress for the ball - as a faux-nice gesture, of course, so they can humiliate her.
Aaron's ex, Lexi, is in town, and when Serena and Dan visit Aaron at the studio Lexi takes quite a liking to Dan. She convinces him to take her to the ball, in fact. That's not gonna be awkward in the least!
Saying that only they can satisfy the other, Chuck and Blair make a deal to choose each other's dates for the ball. Blair will get to use Chuck's limo for a month if he actually likes who she chooses, and if he wins, well, he'll get Dorota for that time. Yikes.
After Aaron tells Serena that Lexi puts out when she first meets a guy, S starts to feel weird about their double date to the ball.
She rants to B about how Dan is going to be seduced by Lexi, but Blair is more interested in the fact that Serena has yet to have sex with Aaron.
Serena tells Aaron that she's ready to give it up after the ball.
B tasks Dorota to find the perfect date for Chuck, but the maid's Facebook groups fail to turn up any viable candidates. Lily decides to forgive Bart long enough to attend the Snowflake Ball with him.
She calls to let him know, but cancels her plan when she finds out he's in a meeting with his PI.
At the ball, Vanessa arrives wearing the dress Jenny designed for her, Lily shows up without Bart, and Blair and Chuck come with their doppelgangers.
The people they found to be each other's dates are basically lesser versions of themselves. Beta Blair and Bass also end up ditching the duo to make out in the corner.
Serena and Dan share a dance at the ball while Aaron spends time with his ex. They share an awkward talk about their upcoming sexual adventures, but Dan's enthusiasm over Lexi only upsets Serena.
While S storms off to wash the icky idea of Dexi sex from her brain, Vanessa tells Jenny that she's going to end things with Nate.
V approaches N and admits to stealing the letter on Thanksgiving, saying she feels absolutely terrible for coming between him and Jenny.
J starts to feel bad about her scheme with the dress, but it's too late to stop her plan. As Vanessa walks through the room, someone shines a huge spotlight directly on her, revealing that her outfit is see-through.
After everyone laughs at Vanessa for flashing her bits in public, Nate tells J that he's appalled by her actions.
Lily pulls Rufus aside at the ball and reveals that she plans to leave her husband. They share a touching moment where Rufus admits that he regrets letting her go, but unfortunately Chuck sees the entire thing.
He calls his dad in his limo and tells him that Lily is flirting with Rufus yet again. Bart plans to head to the ball immediately - but first he asks his PI what he discovered about Lily's time in the sanitarium.
Nate stops Vanessa just as she's about to hop in a cab to head to Brooklyn. He wants to be with her regardless of her letter thievery.
They share a kiss while Jenny looks on, lurking in the shadows as usual.
Blair's bitchy posse no longer wants anything to do with her, but J vows that she'll be seeing them again soon.
Chuck and Blair share a slow dance and admit that they'll never be as openly affectionate as their get-a-room 2.0 versions.
Dan and Serena part ways to go have sex with Lexi and Aaron, respectively.
Lily finds out that Bart has been in a horrible accident.
(Source: TV Fanatic)