Dean Winchester: Before Dad died, he... He told me something. Something about you.

Sam Winchester: What? Dean, what did he tell you?

Dean Winchester: He said that he... wanted me to watch out for you... take care of you.

Sam Winchester: He told you that a million times.

Dean Winchester: This time was different. He said that I had to... save you.

Sam Winchester: Save me from what?

Dean Winchester: He just said that I had to save you. That nothing else mattered. And that if I couldn't, I'd-

Sam Winchester: You'd what, Dean?

Dean Winchester: I'd have to kill you. He said that I might have to kill you, Sammy.