It could have ended there, except for one thing. One of Illyria's unknown powers involved the manipulation of time and time is a dimension all on its own. Which is why time itself became just a tiny bit fractured in the area surrounding where Illyria was destroyed. This was never much of problem and not really noticable, it just meant one person's watch would move at a different rate, a few seconds, a few minutes, than someone else's. And it was a localized phenomenon, extending out only about twenty miles from the place Illyria was destroyed. Again, not a big deal, the area was in the desert after all and uninhabited. However, there was a highway that ran from Sunnydale to Los Angeles and was in the affected area with cities in-between. Again, not a big deal because only military personnel lived in Sunnydale these days and when they had reason to leave Sunnydale, it was usually on assignment and they were flown to their destination. Unless they were granted leave time and didn't take the opportunity to fly out to meet friends or relatives somewhere else. If they didn't do that than they probably drove to Los Angeles or one of the cities in-between to relax for awhile and if they noticed anything at all, it was that they either gained or lost a few minutes and simply dismissed it as not paying attention. Not even Magic users noticed anything because time isn't Magic, even if it was affected, in this case, by Magic.
But one person did notice and unfortunately, or possibly fortunately depending on your point of view, was affected by the damage done to time in this small area of the desert.
Cordelia finished up her day, the last, for the movie she was playing in. When Xander had sent her and Dawn away from Sunnydale so he and the other soldiers could deal with Illyria and he didn't have to worry about them, she'd known she'd need something to distract both her and Dawn. So since she still had to report to the studio anyway to wrap up her last day of shooting, the two had simply gone in early and waited for the day to begin. It had only been a couple of extra hours anyway. Xander had called and Dawn, who'd been holding her phone for her, had answered and relieved both of their minds with the report that this time, Illyria truly seemed to have been stopped. The remains, what there was, were already in the incinerator being reduced to ash. And now the day was done and they were heading back to Sunnydale.
"Xander called again." Dawn informed Cordelia as they left the studio. "While you were getting cleaned up. He remembered me asking if we can move Buffy to New York so I can see her more often and he talked to the General about it. General Higgins has agreed to talk to the civilian office about finding a new facility. They need to do stuff like background checks on everyone and make sure they have good security. Me being Classified and all, they don't want to risk some idiot getting it in their head to study me and using the people I care about as leverage."
"Speaking as one of the people you care about, who also happens to care about you, I'm personally grateful for his diligence. Xander's right, no lab rat Dawn, ever."
"Yeah, definitely not, I just want to be a normal girl, you know? Not have to worry about the Key thing and what it could mean. I can't help but worry and not just about someone wanting to study me. I worry that I can't control what I am, that I might accidentally trigger some ability I don't even know I have just because I'm the Key made human. If it was at all possible for me to stop being the Key, to just be an ordinary girl and not have to worry about stuff like that, that would be the greatest gift ever."
Magic has been described as intent, both the force and the strength of will, imagination, need, belief, emotions and other factors. It doesn't just answer to the spoken, it answers to the unspoken as well. To the deep down hopes and dreams and desires, even ones you don't know you have. Time is a dimension, in and of itself and the Key, can, possibly among other things, open dimensional portals. At the very least, it had a relationship with dimensions. The known and the unknown number of dimensions. Science recognizes four observable dimensions with the potential of possibly 26 mathematically provable dimensions existing.
So what happens when the Key made flesh, something capable of affecting dimensions, passes through a tiny temporal fracture? Time being a dimension as well.
Dawn bent over in her seat with a groan as she felt...something. As intelligent and linguistically capable as Dawn was, there was no way she could put into words what she was feeling. It was pain and exhilaration. It was loss and acceptance. It was emptiness and completion.
"Dawn? What's wrong?" Cordelia asked, glancing away from the road toward her young companion.
"I don't know, it feels like, like something's - ." Unable to finish the sentence, Dawn gasped as she began to glow, an eerie green.
"The base!" Cordelia decided. "We've got to get to the base!" She depressed the accelerator and the car shot forward, racing down the highway toward Sunnydale, as Cordelia clamped down on her fear.
Beside her Dawn seemed to age, then deage, one moment looking as old as Mrs. Sheldon, the old grandmother in their neighborhood, the next, she looked like a child. Back and forth. Cordelia pulled up to the base's guard post, yelling for help, just as the eerie green light pulled completely away from Dawn and rose up through the roof of the car and vanished.
Leaving an unconscious child drowning in a teenager's clothes in the passenger seat of the car.
