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.
Out in the party, the rumors are flying about Serena's disappearance: was she pregnant, was she in rehab, how come she looks so fly if she was pregnant and/or in rehab, et cetera. Serena's mom Lily (Kelly Rutherford, my favorite actor besides Calabro from the entire Melrose ensemble, a woman so beautiful not even her chronic upper-lip melasma can even approach tainting her beauty, a woman of such clarity of mind and softness of heart that, were my insane bald wife to finally succumb to cancer after a weeks-long battle moments after informing me that she'd found the perfect prostitute to be my replacement wife, I would totally be up for it, if that woman were Kelly Rutherford) is being all sassy party mom: "...So I told him forget it. I don't care if it's Murakami, it clashes with my sofa." What this tells us is that Lily has very awesome and progressive tastes: Takashi Murakami is the fine art expression of harajuku, or maybe he's the fin de siècle Japanese version of Andy Warhol; he's awesome. All about blending high and low culture and commercializing art products and artifying commercial products. Besides being a sly comment on the show's hipness, though, it also sets up her connection with Rufus later. Also, she giggles stupidly at her own joke, but she's so pretty it doesn't matter. So Serena approaches, asking if they've let "him" out yet, but Lily brushes aside the questions and says she only invited Serena to Eleanor's party so she could see her friends: like Nate, approaching down the hall, or Blair, jumping out of another door right between them, surveying the scene with Nate's naked and goofy desire and then turning to see its object: her BFF.
Nate disappears (the Timberlake is still playing, of course) because even his stoner ass knows when it's a good idea to evaporate, and Serena and Blair get immensely awkward with each other. There's an awesome steely determination in Blair's eyes at all times, but especially here: she hugs Serena in a fair approximation of excited pleasure. The chemistry is nice, because Serena gets the ambiguity, on top of also feeling awkward for reasons that will be revealed. It's a good moment. She and Eleanor are all like, "Serena, you have to join us for dinner!" But Serena has to bounce immediately: she just came by to say hello. (And ruin Blair's sudden relinquishing of her chastity, Blair thinks, although nothing could be further from the truth, or from logic itself.) Blair sets her shoulders back and her face goes cold, because of the three things she's scared about, w/r/t Serena, the first and foremost is that Serena was not, in fact, kidnapped off the face of the earth and forced to leave Blair in the dark for a year. And that one just came true. Serena promises sweetly to see her at school tomorrow, giving good jetlag face even though she was only coming from Connecticut, and takes off. Blair shakes it off, telling Isabel and Kati that she knew Serena was coming and just wanted to surprise everybody, but neither Chuck nor Gossip Girl is sold: