Serena van der Woodsen: Blair...
[Serena just entered Blair's house]
Blair Waldorf: Serena, what are you doing here? It's late.
[Serena starts to cry]
Blair Waldorf: Oh my God, what happened? What's wrong? Talk to me.
Serena van der Woodsen: I can't.
Blair Waldorf: Of course you can.
Serena van der Woodsen: No, no, B. This is the one thing I can't tell you. I can't tell anyone.
Blair Waldorf: I'm not anyone, I'm me. You can tell me anything.
Serena van der Woodsen: No, I can't because then that would make you a part of it and you can't be a part of this.
Blair Waldorf: What are you talking about? You're starting to scare me.
[Serena cries more]
Blair Waldorf: Hey, hey, hey. We're sisters. You're my family. What is you is me. There's nothing you could ever say to make me let go. I love you. What is it?
Serena van der Woodsen: I killed someone.