I continued. “It looks like a movie theater. Even has a soda fountain in back, and it works. I know because I took myself there—or some Other Me took myself—took him—screw it, you get the idea. One of the other rules you can get around using it is…uh…” I fumbled around for words. “Well, you don’t have to totally…um…go away…”

“The conservation of spatiotemporal presence,” Al offered.

“Yeah,” I said. “That.” I paused. “What?”

“Normally, time travelers will replace their past self when they jump, unless of course they either jump to a time predating their self-awareness or make no significant alterations to the timeline. Even then, going backwards into deep time will often—but not always, the rules are quite complex—replace the original actor, should he have been present on another trip. The In-Between, however, bypasses this restriction.”

“Uh, yeah, what he said,” I blundered. “Time shortcut.”

“So then why can’t we just use the In-Between to go forward to the future in the first place?” Zoe wondered.