depended--or maybe there was no such thing as unity. Mass-energy wasn't
conserved. It was deserved. It was a world of anarchy, from your point
of view. It must have been a terrible place to live, I guess."

He hesitated somberly. "As terrible as this one is getting to be," he
said at last. "Anyway, there were people who lived there. There were the
two inhabited worlds in their own time lines, or probability orbits, or
whatever. You know, I suppose, how worlds of probability would separate
and diverge as time goes on? Of course. Well, these two worlds
_coalesced_."

He looked searchingly at Dave. "Do you see it? The two time lines came
together. Two opposites fused into one. Don't ask me to explain it; it
was long ago, and all I know for sure is that it happened. The two
worlds met and fused, and out of the two came this world, in what the
books call the _Dawnstruggle_. When it was over, our world was as it
has been for thousands of centuries. In fact, one result was that in
theory, neither original world could have a real past, and the fusion
was something that had been--no period of change. It's pretty
complicated."

"It sounds worse than that," Dave grumbled. "But while that might
explain the mystery of magic working here, it doesn't explain your sky."

Bork scratched his head. "No, not too well," he admitted. "I've always
had some doubts about whether or not all the worlds have a shell around
them. I don't know. But our world does, and the shell is cracking. The
Satheri don't like it; they want to stop it. We want it to happen. For
the two lines that met and fused into one have an analogue. Doesn't the
story of that fusion suggest something to you, Dave Hanson? Don't you