It's been a long two weeks, but Gossip Girl is back! Not one couple makes it out of this episode without some serious threats to coupledom. We'll take a page from Gossip Girl's own medical theme this week as we delve into the health of each love connection.

TROUBLING SYMPTOMS
Lily and Rufus: Serena finally knows her mom's secret: Lily's sick with something that sounds cancer-ish, but no one actually says what it is. Lily's getting treated for her shmancer by none other than Serena and Eric's dad, Dr. William Van Der Woodsen. Rufus hates him and tries to banish him, but his oily Baldwin charm and Lily's apparent shmancer relapse mean he's sticking around. He's shady as hell, ending the episode with a call to some mystery person saying his "plan" isn't working out and he needs another prescription for Lily. Like we said, shady! But he seems to be trying to make up for lost time with Serena, who just barely resists falling into his arms and calling him Daddy and telling him the names of all her My Little Ponies. Give it a week.
Dan and Vanessa: Dan didn't get into Tisch. It's 'cause Vanessa took his spot. He thinks she did so by accidentally violating the rules, and Willa takes that ball and runs with it, trying to get V kicked out so D can get in. Turns out V didn't violate the rules, and D did everything he could to stop Willa. But did that stop Dan and Vanessa from ending the episode with their now-standard "You fell short of my impossibly high standards and we are terrible at communicating so now let's sigh at each other and look betrayed" fight? No, it did not.
Chuck and Blair: Blair wants the world to know she and Chuck are done — like  really done. Only one problem: Chuck's put a 'dating fatwa' on her, and no Upper East guy will come near her for fear of a Bass attack. So Blair invites herself to Dan's Bushwick party where she latches onto the first vaguely uptown guy she finds — a Columbia hottie — so she can snog him and plaster it on Gossip Girl. But she realizes such a petty gesture won't help her move on, so Queen B goes home unkissed to mourn her relationship properly. She should have gone for it!
Nate and Serena: Chuck wants Nate back. In a friend way. He decides this will be "easier with Serena out of the picture" (really? okay) and he plays a sort of anti-matchmaker, coaching Little J on how to break Serena and Nate up. They almost get away with it, convincing N that S doesn't care about him, and making S think that N is hooking up with Jenny. But Serena comes to see Nate and they realize why they've had so much trouble communicating: They've been trying to do it through Jenny, a sociopath who wants to sleep with Nate. Nate kicks Jenny out and he and Serena get all gooey again. And then probably head off to have sex in a meat locker or on a bike rack or something.