Blair invites both Chuck and Dan to her birthday party -- everyone who's anyone, including teenagers! -- and S calls Juliet because B doesn't want any of her damn mess. Juliet offers to accompany S to the party as a "buffer" in the professor situation, I guess so that if S just loses control and turns into the sex werewolf she clearly fears is going to happen, Juliet can jump in the middle of it and have sex with Serena instead? Whatever Juliet's plan is, GG thinks it's brilliant, but I don't know. It seems like taking the long way around. Serena loves it, even after Juliet points out that the birthday girl won't be happy that her enemy is at her party -- not to mention the fact that every time S is civil to Juliet in any way it just makes her look like a brain-damaged golden retriever, because the bitch is clearly after her and has done at least one awful thing to her every week -- at which point Serena is like, "Who is Blair to decide the invitees to her own birthday party, at her own house, in which I am myself a rent-free guest?"
Dan calls up Nate to make fun of the peace treaty, and Nate's like, "Yeah, that was my idea? So..." By way of apology, Dan is like, "Yeah, by the way your friends are assholes. You have really bad taste in friends, and generally, and also you are a bad person. But we're best friends still!" Nate says Dan should not be asking about the treaty, because it has secret provisions, and when he mentions S was there too Dan has the fuckin' audacity to be like, "I thought we agreed that I can hang out with Serena whenever I want but you can't!" Because he is a sweetheart and because he is slow, Nate apologizes for hanging out with Serena, even though that agreement has been broken about eleven times by Dan, and then Dan totally steals the peace treaty before the Empire security guy can come put it in the safe. (PREPOSTEROUS!) Gossip Girl gloats girlishly: "Nate thought he and Humphrey were thick as thieves. Turns out Humphrey's a thief, and Nate's just thick..." Turns out this episode is amazing, and Gossip Girl is kind of a shitty person. But we knew that.
Serena goes to find Nate and tell him she's dating Juliet now, and he's like, "Fucking figures." She explains that it's just for tonight, and the whole sex buffer thing, and Nate is like, "I'M SO IN!" As long as Humphrey's getting all jello about Nate seeing other people, he might as well earn it by actually breaking their stupid agreement. S isn't sure about that, because it's not about making Colin jealous which is why she would normally go anywhere with Nate, and points out the stupidity of this entire plot thereby; Nate makes a fully nonsense argument ("Let's be honest, it's better to have a guy protect you from another guy") and because it's the Twins talking their nonsense language at each other, Serena is convinced. She calls up Juliet and breaks their date, and Juliet responds by scratching out all the eyes in every picture of Serena she has on her corkboard. It takes a long time because there are like a million pictures of Serena in her house.