She wasn't particularly expecting to witness any accidents today, but she took her training seriously, and has been tirelessly watching the seas all day. She sees the girl fighting to keep her head above water, sees her dip below the waves, and leaps into action. The girl is successfully pulled from the water. When Mercy determines that she isn't breathing, she barks at one of the other girls to call 911, then starts administering CPR herself. She doesn't expect the CPR to work, it's far less effective in real life than it is in the movies, but she has a duty to protect everyone on this beach, and she intends to do her best.

She comes to, coughing and spluttering, about a minute before the paramedics arrive on the scene. It takes her a couple minutes to remember that she has parents, and a few hours to be pretty sure that she doesn't anymore.

Her sister, who is not a fan of boating and has been sunbathing all this time, drives her home. Apart from some mumbled logistics regarding the fact that Karen can obviously stay in her house as long as she wants, and that they can sort the rest out later, they don't talk on the way home.

She has nightmares that night. She had nightmares last night, too. They are mostly not about water. Mostly they're about fighting vampires. She kicks them around looking for some kind of deep symbolism after she wakes up, but mostly doesn't find any.

Her sister plans a funeral, makes some vague motions in the direction of becoming her legal guardian (Karen's not clear on whether she actually does anything to make this happen), and talks idly about how Karen will probably have to transfer schools in the fall. And so she lives with her sister and her sister's son Connor, in the little California town where fate has happened to drop her. 

Sunnydale is a pleasant, sleepy little place, with a half-decent public library, exactly one nightclub, and a truly excessive number of graveyards.

But the really interesting things about it don't become obvious until you stay out after sundown.

She is not the sort of person who normally wanders around town after dark, but her parents just died. She takes to visiting the grave every couple days. About a week after the funeral, she visits it on her way home from the library. It's not pitch black outside, but it's decidedly after sundown.

A woman with a leather jacket and a really dated haircut is approaching the graveyard gate from the other side as Karen arrives. She offers a friendly smile, stands aside politely to let Karen through, and then grabs her and attempts to bite her neck.

Well then.

She doesn't exactly think about punching the woman in the solar plexus as hard as she can, but it seems like the thing to do, so she does it.

The woman grunts unhappily, staggers back a few steps—giving Karen a good look at her face, which is locked into an inhuman snarl that lifts her lip away from a pair of fangs she didn't have a moment ago—and then attacks again.

"What is wrong with you?!" she demands, while simultaneously kicking the woman in the stomach. She honestly has no idea how to fight people, she took free church karate lessons for like six months when she was seven, she's pretty sure that doesn't constitute knowing how to fight people. She's also pretty sure you're supposed to run away if someone tries to attack you. Maybe she should be running away, but then she won't get to figure out what's happening - that's a bad thought, she should run away anyway, she has no idea what she's doing -

The next time the woman comes at her, she grabs her, flips her, and sits on her.

"What do you think?!" she growls, struggling ineffectually.

"I don't know!! I generally assume that people in civilized societies have better things to do than attack random passersby!!" she yells, probably much more forcefully than is strictly necessary.

"Ugh, are you for real?"

"...yes?"

"What are they teaching you these days? Whatever, I'm outta here."

A moment later, she finally succeeds in squirming out from under Karen, and immediately bolts down the road at a frankly astonishing pace.

"...Bye?" she says, before wandering off back in the direction of her house.

A couple of streets away, a boy who looks older than her but not by very much emerges from a shadowed alley and falls into step with her, with as much of a polite distance between them as the width of the sidewalk affords.

"So you've seriously never heard of vampires?" he asks.

"...I have heard of vampires," she says carefully, preparing to run if she needs to. There's no way she didn't just get lucky last time.

"But you didn't expect to get jumped by one walking around Sunnydale after dark. So you haven't heard of, like, real ones."

"I have not."

He sticks his hands in his pockets and gives a wry half-shrug. "Well. Surprise!"

"Uh-huh," she says, sounding fairly unconvinced.

He glances sidelong at her, and—

—there's a quiet, horribly biological sort of crunching sound, and his forehead hardens into a ridged caricature of a predator's snarl, and his eyes lighten from dark brown to a pale wolfish yellow, and his upper canines lengthen visibly into fangs.

"Were you not paying any attention when that lady jumped you? C'mon."

She backs away and drops into what she hopes at least looks like a decent defensive stance. The first thing her brain gives her is what are you guys?, but she's pretty sure of the answer she'll get to that one, so -

"OK. So. You're - vampires, or whatever."

"Vampires!" he agrees, reverting to his human face and continuing to make no aggressive moves whatsoever. "Real actual vampires! And demons and stuff! I'd take you to the demon bar to prove it, except if I take you to the demon bar somebody's definitely gonna die."

"I am in favor of not dying," she says. "Also I don't go to bars."

He laughs.

"Anyway. Hi, I'm Zeke, I will be happy to answer all your vampire-related questions if you promise not to kill me."