Cara didn't ask to be stationed right on top of the Hellmouth. She certainly didn't ask to put her extremely expensive education to use trying to convince a bunch of drooling American teenagers to pay attention to Latin verb conjugations. In fact, she'd strongly prefer to avoid demons, non-Slayer high school students, and other such unsavory creatures altogether. But, well, she's the one who decided to become a Watcher. She made her bed, she has to lie in it.
Of course, when she signed on, she didn't expect a missing Slayer.
The girl seems to have vanished off the face of the earth, which, of course, means demonic activity is skyrocketing. And, of course, Cara's the only one around with even the tiniest chance of keeping it in check. Which is why she's poking around in the boiler room during her lunch break instead of popping another aspirin and taking a nap on her desk.
Whoever this missing Slayer is, she'd better have a damn good explanation.
"Are there soulless creatures who do seem to experience remorse? Maybe souls are just a correlate."
"It's possible. Neutral demon species do exist, but they're not friendly enough for us to find out whether or not they feel remorse. It's difficult to determine how souls work. You can't exactly take one out and poke it until it makes sense like you can with other body parts. All we have to go on is behavioral analysis. And on top of that, most behavioral analysis is done on the types of demons who kill people, so the information we do have is biased. If I were magically invulnerable somehow I would try to get better data, but the sad truth is that the vast majority of demons would eat my face as soon as look at me, which makes data-gathering difficult. I'm quite attached to my face, and most other parts of my body as well."
"That's usually how body parts work. I do appreciate the complications. I am curious about neutral demon species in general. Does Spouse Book know more?"
"Spouse Book does, in fact, know more. 'Neutral' generally means 'will not attempt to remove your face from your body without provocation' or 'does not generally interact with humans' as opposed to 'friendly', but neutral demons are fascinating all the same."
"Part of what I'm wondering is whether any of the neutral demons dislike any of the non-neutral demons."
"If you're looking to recruit allies, it's a good idea, but most neutral demons strongly prefer to avoid conflict. I'd be happy to assist you in convincing them, but, again, tread carefully. Sometimes it's difficult to know what constitutes provocation."
"Lazy bastards with deeply confused moral sensibilities and absolutely no backbone."
"That's an idea," she says. "I don't know that anyone's ever tried, but I don't see what's stopping us."
"Well, my total inability to do magic, for one thing, for all I know one can only get root access to the involved apparatus if one is personally the Slayer. But it seems worth looking into. Several hundred volunteer background-checked Slayers! Who are maybe already out of high school!"
"What? You mean trained volunteer adults tend to be better at doing important jobs than coerced and untrained teenagers? Someone alert the media," Cara jokes. "The magic issue could be a barrier, but even if it is, we can at least find out how a Slayer with magic would theoretically go about editing the system."
"And pass it on to my successor. Fun stuff. But maybe you can do it or some other witch can do it."
"Yes, pass it on to your successor after you live to a healthy age," she says decisively. "You're right, though, it'll only be a problem if it's a spell only the Slayer can perform."
There follows considerable Slaying, mostly from safe-ish distances and indirectly via morgue stakings. There is a field trip to L.A. for dusting vamps, leaving ominous graffiti, and having confidential chats with a few morgue workers. Bella finishes crossing the town of Sunnydale. She reads more about demons, and manages to quell an infestation in the south side. She learns Latin. She doesn't do very well in most of her other classes, but she passes.
(Her students have noticed that she's become a lot crabbier during class, has started drinking a lot more coffee, and seems to be relying on educational videos and in-class work time to fill her class hours while she reads at her desk.)
Her research points her towards a scythe that can theoretically break the Slayer line to a degree by calling all Potential Slayers at once. The scythe is retrieved, and Cara begins performing experimental spells on it to try to expand its range (five hundred coerced teenage girls is better than one coerced teenage girl, but not by much).
It's long, thankless work, and she desperately wishes she had another witch to help her out.
One afternoon, she takes a long, profanity-laden walk to clear her head. She ends up in a mostly-deserted park.
Cara would prefer not to have company, but the only other bench nearby appears to have been vomited on. It's a close call. She grunts noncommittally at the other person, then buries her head in her hands.
"Brilliant observation," she snaps. "Pardon me, I didn't realize I was sitting next to bloody Sherlock Holmes."
"What, do you have nothing better to do than sit around in parks and listen to people whinge at you?"
"Here's what going to happen," she says. "You are going to sit there and listen to me. You are not going to butt in with personal anecdotes or unwanted advice. You are not going to tell me I sound like I'm insane, even though objectively, I am going to sound like I'm insane. You are not going to get your feelings all over me. For the purpose of the exercise, you are going to sit there like a wall that occasionally nods and says 'go on.' Come to think of it, I could just go home and yell at a wall..."