Now she glanced at Mark’s position in the motel, now swept back out to the woods, watching for any sign of movement. But all was quiet. Mark’s heart rate had slowed to 58 and his brain was flirting with alpha. He was napping, which was good. Among the skills he had developed was a sensitivity to the odor of hybrids, and he would not be this relaxed if he could smell them.

Lifting the stick, she swooped up out of the town to an altitude of fifty thousand feet. Then she went down into Big Basin State Park. She’d been through here a hundred times. It was one of her highest-priority locations because of an event here, in the summer of 2007, odd enough to come to her attention.

A group of cyclists gazing across a valley had photographed what was perhaps the strangest-looking object that had ever appeared in the skies of earth. It had a central core of large metal plates affixed to an inner circular gridwork, with wide beams jutting out of it at three angles. Above this rose a forest of twelve tapering antennae that seemed to grasp at the sky. Below it, pointing toward the ground—ominous, somehow—was a long spike.

One of the cyclists took a picture with his cell phone, which duly appeared on the Internet. She’d e-mailed the photo to Dr. Turner, who had sent back a note saying that it was a Photoshop job and to forget about it.

Gina had consulted her register of known forms of guided craft and found nothing like it.

Dr. Turner would say things like “Given that they’re in advance of us technologically, we can expect them to also be in advance of us ethically.”

It was not for her to criticize him, but it did occur to her that we’d already been civilized for four thousand years when the Holocaust took place, not to mention the rise of communism and Islamic and Christian fundamentalism. The idea that older civilizations automatically become more ethical did not actually wash, but he made the policy around here, not her.

She went back to the murder woods. Still nobody nearby. But it was only a question of time, wasn’t it? She knew that she should move that farm family out of there and send state cops to flush out the campers.

She called up a computer-enhanced image of the three people whose appearance here two weeks ago had caused her to send Mark to the area in the first place. As she had a dozen times, she zeroed in on the clearest face, which was that of a woman. She’d measured that face with great care, and all the ratios were well within human norms. That white sheen was the only difference. Why was it there, and why didn’t all of them display it?