"URA Fever," the song at the end of the episode, starts playing in the background as Serena looks up to see Georgina, shoving her hand in her face: "Hi! I'm Sarah. It is so nice to finally meet you." Serena shakes it off and sticks out a hand, but the key is in the lyrics, again: "You only ever had her / When you were a fever." Because when Georgie was a fever, she burned with Serena, and they were whoever they wanted to be. She was the other side of Serena, the bad girl, Blair's opposite, and they burned with each other. She only ever had her when she was a fever. They could go out to the edge and always bounce back, when she was a fever. They could get out of control, or not go out of control, but at the end of the night somebody would catch them.
But that night a year ago, something happened. I don't know exactly what it was yet, but something broke. They crossed the edge together, and Serena just left her there. And now she's a fever all the time, but she burns alone.
"Wow! I mean, Dan told me you were pretty, but he didn't do you justice." Serena asks to talk to Dan privately, but Sarah talks a mile a minute: "Hey, no, no, no, wait, don't go. Vanessa was just about to show me one of her movies. I'm a filmmaker, too, of sorts. Actually, I brought one of my short films, I was hoping to get your opinion. Maybe you wanna see it, too, and tell me what you think?" She plays with a USB drive, looking in her eyes. Vanessa runs off to grab her laptop, and Serena asks Dan to get her a coffee. He doesn't move fast enough, because time's slowed down for her, so she repeats her request, sharply: What she says is "please," but what she means is "now." He leaves, resenting it -- wanting to see Serena and Sarah become friends -- and Georgina smiles at her, and leans closer.
"What the hell are you doing, Georgina? Put that away." It wasn't just Georgina she left in the dark that day; she's spent every day enduring all manner of shame and Dan Humphrey bullshit to forget it ever existed. That's why Georgie's back now, on one level of the story: Serena can't be whole until she reconciles her Blair side with her Georgie side, and stop pretending it doesn't exist. Right now she's trying to be Dan, which isn't going to work. Eric's a step in the right direction, because this is the part of the story he's figured out, he's dragged himself out of the dark and all his shame stuff came out with him, turned to gold. It's why you can trust him with Chuck, because he can see it without being scared of it. But not Serena, yet, so you got Georgina right up in her big old face, demanding to be noticed. To not be ignored. Lighting every type of fire, in every location, to get Serena going again: Dan, Eric, the sex stuff, the drugs, whatever it takes, to get her back and let the fever burn.