"Rats go underground, not Waldorfs!" Serena follows Blair into the house of PRADA and laughs at her, mentioning Chuck's helicopter for the hell of it, and Blair sighs extravagantly. "Chuck. What a waste of time that was. You know, it's not a real relationship if you can't hold hands..." (So I don't know if you've seen TV before, but like obviously they're going to somehow ending up holding hands at some point in this episode.) Then she hops into that druggy, dreamy Nate talk that's getting so boring. Serena points out that part of Nate's renaissance in the boudoir is probably due to him being a total prostitute most of the time, and Blair's like, "But I won't take the subway for that ho either."
Blair changes the subject to Serena's eponymous "foreigner" Gabriel, popping a grape in her mouth. This is true friendship, because it would take an act of Congress and six Vicodin for me to sit through even five seconds of Serena talking about Gabriel. It's like he makes her more boring than she usually is when she's dating. But if he's boring, and Serena's being boring, then where is the surplus amazing going? Georgina Sparks, I think. Serena points out that North Carolina is in fact part of the US, but Blair yells, "Not by choice!" Heh. Serena laughs and says some snoozeworthy thing about how perfect it is with Gabriel, except for how he's never around. Which for anybody else would be like a neutral-to-good thing about your boyfriend, but for Serena it's like being in space without oxygen, because Lily fucked her up good.
"Well, if it's casual like you say, no strings, then what do you expect? It's not like you're gonna marry the guy," Blair says, and then Serena admits that she "kind of did" marry him, which we already know is not true whether or not Cyrus says so, so what a weird conversation to be having at this point, and then it goes on for a little while. Basically Blair decides that Gabriel is secretly up to no good and needs to be stalked. "We can dress up, use code names, Dorota is a great help with surveillance equipment... Doesn't that sound at all fun?" Only with you, Blair Bear. Serena stares at her like she's crazy and tells her firmly but lovingly not to stalk Gabriel, tapping her on the forehead and walking off. Blair immediately begins planning the mission to stalk Gabriel, partially because Serena is an idiot right now who got distracted by the lupine teeth and height, but mostly because she's entirely bored with Nate and can't admit it without the whole thing falling down.