Serena begs Blair not to embarrass Chuck in front of his entire gala, and Blair is like, "Have we fuckin' met?" She pretends that's not what she's going to do, but they have to get dressed anyway because they're going, and then B condenses a fact from the vapor of nuance: Serena has decided to steal Dan from Vanessa Abrams. Which is bitter and sweet in equal amounts: "As much as nature would applaud you for heading off any possible future Humphrey/Abrams offspring, you have to ask yourself: Are you ready to do what it takes to make him yours?" Love -- love -- how the possibility that anyone could ever love Vanessa Abrams, and therefore the idea she could have a relationship with anybody, are so laughable they don't even consider it.
When Dan gets home from his date with fake Nate and real Serena, Rufus is putting things in boxes so that Dan and Vanessa can have even more room for their fake marriage. Dan immediately admits that he lied to everybody and went to the park with Serena, and of course Rufus jumps to the conclusion that Dan is gearing up to cheat. Which he is, and it's one of the things I like about this episode, the way everybody's secret creepiness is even closer to the surface than normal. Because it's not really even about Serena, it's about getting away from Vanessa, who has a key to unlocking something that Dan can't face and won't leave it alone. Dan promises it's not about Milo -- "I don't need to be an adult anymore" -- but Rufus points out that he's not just having fun and blowing off steam, he's lying to the woman he lives with, which proves it's more important than that:
As Rufus well knows, the next step is leaving scarves around the apartments of insane psychiatrists who are prescribing fake medications to give your wife pretend cancer.
Dan worries that maybe he only invited Vanessa into the loft because of the Milo situation, and that he has wrecked everybody's life considering right before Georgina showed up he was going to follow Serena to Paris and confess his love for her, but then the phone rings and it's Nate and he gets that funny feeling in his tummy and runs around in little circles. But Nate's not calling just to talk the language of the bros, no, he's calling to say that Vanessa just showed up and he lied for Dan because clearly he's cheating on her, because you have to. "I'm not cheating," Dan promises, "But I was with Serena."
Nate's feelings are hurt, because they both agreed to stay with their respective girlfriends and not bother with S anymore. Dan says it's a special circumstance, and Nate sweetly goes, "Okay, forget me. If you wanna be with Serena, you gotta say something to Vanessa." Like, how nice of you to recuse yourself from this situation, because you know Dan cares way more about that than any of these ridiculous girls. But then Nate's assumptions about Dan's love take another blow: "Serena and I were helping Blair, we investigated Chuck's new girlfriend... That's really all I can say. Blair made me promise."