You've seen this before, I'm sure. The person lists a CSI quote without saying who said it or what episode, and the next person writes the character and episode the quote is from. If it's a two person quote, use Person A and Person B (or some other ambiguous label) to differentiate. An example:

Person A: I, uh, I just want to say I-I ... well, I really admire the gusto with which you approach your job.
Person B: Are you hitting on me, Person A?
Person A: Uh ...
Person B: Let me give you some friendly advice. If you want to pull chicks, you've got to get aggressive. You've gotta drop the glasses, lose the coat grow some scruff. You do get a "C" for cute, though.

The answer would be David and Sara, "Friends and Lovers."

Let's start with an easy one.

"You infected me with mildew?"