Dr. Vale, for his part, spent his time poring over Morgan’s copious records of Partial genetics, trying to reconstruct as much of his work on the expiration date as possible. When Kira wasn’t on the operating table or in the recovery room, she sat with him, usually attached to a rolling IV, and tried to learn as much as she could.

“This is part of the aging sequence,” said Vale, pointing to a segment of a DNA strand glowing faintly on the screen. He highlighted a series of amino acids with his fingers, and it glowed a different color. “A normal Partial grows to physical maturity in about ten months, all inside of a big glass tube; we called them vats, but they really looked more like those clear capsules you’d use at an express diner.”

Kira shook her head. “I have no idea what that means.”

“Sorry. How about a . . . skinny glass elevator?”

“I was five years old at the Break,” said Kira. “I grew up after the world already ended. You’re going to have to explain this without old-world metaphors.”

“Okay,” said Vale, pressing his fingers to his lips as he thought. “Okay. Imagine a clear cylinder, about seven feet long and two feet in diameter, with a metal cap on each end full of tubes and hoses and such. We had a few of them in the ParaGen building in the Preserve, I should have shown you; the rest were all at the growth and training facilities in Montana and Wyoming, but those were pretty heavily bombed during the Partial War. Anyway: The techs would create the zygotes in a lab and plant them in a nutritive gel Dr. Morgan invented, and by the time they were done growing, they more or less filled the tube; them and all the liquid we pumped in with them. I designed the entire life cycle,” he said, pointing back at the glowing DNA strand on his screen. “They required a remarkable amount of energy to grow at such a rate, most of which they drew from Morgan’s gel, though we had to keep them warm as well—the infant Partials were designed to be so energy-efficient that they lost virtually none of their energy as heat, which helped them grow quickly but kept them unnaturally cold. Once the accelerated aging was finished, the heightened metabolism slowed down, and they live relatively normal lives, but when the twenty years are up, the age accelerator kicks into overdrive—it looks like they’re decomposing, but really they’re aging a hundred years in a matter of weeks.”

“And freezing to death at the same time,” said Kira.

“Well, yes,” said Vale. “The energy has to come from somewhere.” He sighed. “I know you don’t approve, and I assure you that I don’t either. I didn’t like it then and I don’t like it now. But there was no other way.”