Flying in the helicopter, he felt like Faust being shown the world by Mephistopheles. Except here Satan was his own father, offering him a teasing prospect of what it would be like to live on and on.

It would make a hell of a story. The problem was, miracles always came with some kind of terrible price. What was the price this time?

Then he had another thought. Was that what had happened to Kristen? Was she paying the price for some kind of hubris that pushed nature too far? Nobody had claimed she had any kind of medical condition that necessitated a stem cell intervention. So had she been experimenting with some other procedure? Had Mephistopheles now called in his marker?

He wanted to ask but the vibration and the noise made his brain feel like it was in a blender.

"Do you understand what I'm saying?" Bartlett went on. "Do you want to be part of the most exciting development in the history of medicine? Well, this is your chance. There is a majestic experiment under way. But now we know it's not for the fainthearted. The question is, do you want to live life or just write about it?"

"I think it's time I heard the whole story," Stone said finally, forcing out the words. "What's your part in this 'experiment'?"

"I've put everything at risk, but now I'm this close to controlling the clock. So . . . are you my son? My flesh and blood? Do you have the balls to try it too?"

Stone suspected the question was rhetorical. He was already up to his neck in whatever was going on. He just didn’t yet know how big a part of it he was. While he'd been sedated overnight, had they started experiments on him?

He knew that some of the buzz about stem cells involved the fantasy that someday they might be used to forestall the aging process. Responsible researchers all said that they weren't trying to extend life; they were only hoping to make a normal lifetime more livable. Rejuvenative medicine. Winston Bartlett, however, had just taken stem cell potential to its obvious conclusion; he was talking about doing what others did not dare. Regenerative medicine.

"What would we give to be able to look forward to thousands of mornings like this, ending it all only when we chose?" he declared his hands sweeping over the dense green beneath them. "Time would become something that merely flows endlessly through us, ever renewing. So‑called old age would cease to exist, at least for those with the courage to take the necessary risks."