So I'm at the library, and I go upstairs to the older books. My friend's dad, who works at the library -- let's call him "Dayle" -- comes up to me and hands me a folded piece of paper, saying "Somebody dropped this off for you." On the paper, it says "for you" in handwriting I didn't recognize. I unfold it, and in different handwriting, it says "go to aisle x599."
Naturally, I go downstairs to the commanded aisle, and on the floor, I see a reciept for a book. Then on the shelf, I find an unsigned library card and a scrap of yellow sticky-note that says, in cursive, "what do you think were those puffs? If they were they in CA winter or summer?" I have no idea what is going on, so I go back upstairs and ask of Dayle, "What did the person look like?" Smiling, he says, "Well, that's a tough question to answer; she asked me not to identify her."
He acted like he knew who it was! But he said he couldn't tell me anything, except that I "don't need to worry; it's not a stalker or anything."
Then, I go back downstairs and, on a table, I see a folded piece of paper that wasn't there before! I launch myself at the table like a nuclear warhead on a sugar high, and open it up to read these words: "Use the card!"
I scan the card into one of those self-checkout computers, and discover that the person's account is blocked because they $18.45 in over-due fines.
Unfortunately, I had to go before I discovered anything else, but I left them a note, saying "I have to go. Continue later? I'll be back at the library next tuesday."
More on this story as it develops.