You are asking yourself how it works. If you care to read the journal, you will know. But if you are in haste, know this, time is not a river but a vortex, and with enough power a man can jump into another part of the swirl.

So, my dear Contessa, pull the lever. Think of the moment you want to be in as you leap into the maelstrom. You will end in the moment you imagine.

Be warned: The machine will go with you, but it cannot stay long in another time. To return, you must use it again before it disappears. I do not know how long it can stay. I do not know what will happen if you make it back to the time you are in now, or what will happen if you don’t. I give you only the means to change your destiny, or perhaps all of our destinies. Use it if you will.

But the book wasn’t Leonardo’s. She’d known it from the first words of the dedication. She turned the page.

My God.

The writing of the central text was done from right to left. Each letter was written backward. It would read correctly in a mirror. Exactly how Leonardo wrote his notebooks—why, no one knew for certain. Diagrams, calculations in the margins, long batches of text that would take many hours to translate . . . it all looked amazingly authentic. And on the final pages, there was an intricate picture of a machine with incredibly complex interlocking gears.

“What do you think?”

Lucy looked up at the girl. The look in those blue eyes was cynical, but only on the surface; underneath there was a terrible, wrenching . . . hope.

Lucy managed a shrug. “Well, if it’s fake, it’s one hell of a fake. The paper is made from macerated rags rolled out in a press. The writing is in the manner of Leonardo. There’s a chance it’s real. I’ll know in a couple of days.”