Back in Blair's bedroom, stoner Nate is a bit slow on the uptake as to what she wants. Even as she's straddling him on the bed, he's like, "What's going on?" She explains that it's time for them to do it, because they've been dating forever and until just now she was planning on waiting. "Not anymore," she grouses, and tries valiantly to, in the classy words of Gossip Girl, "lock it down with Nate."
Out in the party, Chuck's looking forlornly after Nate, having co-opted Blair's Minority Henchstresses, Kati and Isabel. They all like to lie around on couches together all the time looking bored and saying jaded shit. One of them -- doesn't actually matter -- gasps at the Gossip Girl update that Serena's back in town, and Chuck oils out: "Good. Things were getting a little dull around here." Lest you think that's a sign Serena's going to do anything active, or horrendous, I'll tell you right now he's just looking forward to shit-stirring and total bitch drama, and doesn't really care from what quarter it comes, as long as rape is on the menu.
Serena hops sweetly out of her cab downstairs while Blair and Nate are declaring their undying love for each other; JT's "What Goes Around" plays and Serena enters the apartment. Because she went around to Connecticut, and now she's coming all the way back around to Manhattan, see, but also because she dogged her girl, and the consequences are about to holler back. I don't fully understand these terms I'm throwing around. So it's back to the whole "OMG Serena" thing for not the last time, as everybody in the party starts yelling her name and getting all excited. I'm sure people are texting about it, but we don't see that. Nate pushes up from the bed under Blair, for all the world like a prep-school Jonathan Harkness, blearily moaning, "Serena?" Blair tries to push his hot ass back on the bed and keep macking, but for once his concentration is unfazed. "No, I just heard your mom say she's here! Don't you wanna go say hey?" He bounds out of the room and into the hall. Blair's like, "Yeah...totally." Maybe she throws up a little bit.