Kaylee is chipper as ever.  At the end of the day:

"You were going to see Giles after school today, right?"

"Yeah, that was the plan."

"I've got Creative Writing Club today, but I can join you afterward if you want, if you're still here."

"That'd be great, thanks!"

"No problem!  See ya!"

"See you!"

And she's off to the library.

"Nausicaa," Giles says when she arrives.  "Come in, sit down."

"Hey! Uh, what should I call you by the way? Mr G, G-man..."

"Giles will do fine, Miss Uzun."

"Sure thing G-man," she says, voice teasing.

He rubs his forehead, a bit theatrically.  "I think this is the beginning of a very tiresome friendship."

"Acknowledging we're friends already puts you a few steps ahead of some people I've befriended, honestly."

He smiles, briefly.

Only briefly, though.  "Miss Uzun, I'm afraid I have some rather - unjust news for you."

"Huh? What's up?"

"It is a matter of some discretion.  Can you be discreet?"

"...Yeah?"

He emerges from behind the library counter, holding a very large, very visibly old book - the sort of book to which "book" does not do justice.  It is a tome, a grimoire, printed, she can see, with the word VAMPYR in ornate bas-relief script.  He flips through it expertly; he's clearly read and referenced it many times before.

"The man who attacked your friend Kaylee," he says quietly, placing the book on the table, facing toward Nausicaa, "looked like this, didn't he?"

The page shows a sketch of a distorted human face.  It is not the same face as the man who attacked Kaylee, but it is, quite obviously, the same distortion.  The wrinkled, rough, contorted brow, the lips bared and pulled back, the teeth sharp and the canines overgrown; a caricature of a predatory snarl.

"...You really want me to believe vampires exist?"

"I'm sorry to say I want you to believe a good deal more than that.  You said you've been strong enough to win fights with adults all your life, but I think you're shortly going to find yourself stronger.  Faster, more athletic, more durable, more graceful.  You may develop a supernatural intuition for who is and is not a vampire - they don't always look," he taps the page, "like this.  You - have probably already had a great deal more nightmares than usual, and will continue to do so.  If I'm right about you, Miss Uzun, you're something called the Vampire Slayer."

"You're screwing with me."

"You've already heard that the gangs in Sunnydale are enamored of barbecue forks?"  He taps two fingers against his jugular vein, about an inch apart.  "Fangs.  I can secure access to several coroners' reports that will show people with parallel puncture wounds in their necks and drained of blood."

"Yeah. You know what, that'd probably be best." She shakes her head. "Look, I'll hear you out okay? It's not like I haven't heard weird shit before."

"It may take several days to obtain the autopsy reports.  I'll proceed with the essentials today as though I have already produced it, and we can talk again once I have photographs, if that is agreeable."

"Fine." She crosses her arms a bit defensively.