Casey was becoming convinced. He’d gotten that speculative look, in spades. “Your little lunch box over there works?”

“Of course it works,” Brad said through gritted teeth. “We successfully moved the gears today using a fraction of the power it’s capable of.”

“Could you go to the future?” Casey stared at the machine, even though he was addressing Lucy. He was caught by the possibilities. He would be the one to use the machine tonight. Maybe that was okay. But it didn’t feel right. She shook herself mentally. What was she thinking? She had to get out of here or something . . . momentous would happen.

But she answered anyway. “I don’t know. Leonardo was more interested in understanding the past. I guess if time is really a vortex you could go either way.”

Casey continued to stare. “What if you can’t power up the machine again once you’re there?” Oh yeah. She’d been through that possibility in her mind a thousand times.

“According to Leonardo, the machine can’t stay in another time forever. It’s too much pressure on the flow of time. It’ll snap back to where it came from with you or without you.”

“If he knows what he’s talking about. And if he doesn’t?”

She took a breath. “You get stuck there, along with your machine.” There. That should make them think twice about using it.

Brad looked desperate. He wanted the project to succeed that much. “Look,” he said. “There’s always risk. Somebody has to be first. Chuck Yeager had to go up and fly fast even though nobody knew what would happen when you broke the sound barrier. John Glenn had to go up in Friendship I. Sometime, somebody just has to do it.”

Casey peered at the illustration in the book, then straightened. “I agree.” He turned to Lucy. “How about her?”