“Short of the notch,” Payton repeated. Absorbing the implications of Scarborough’s words at once. “Which would be approximately where the rover lost contact with base.”

Scarborough nodded.

“I don’t understand,” Payton said. “If that’s as far as Scout traveled, that is where it still ought to be.”

Scarborough might have agreed that was the logical conclusion. Except the probe wasn’t there. And though a slew of possibilities had occurred to him, none convincingly accounted for its MIA status.

“We’ll keep going. See what’s what,” he said. “I wish I had a better plan.”

Payton thrust a hand at him, palm up. “Pass me the binoculars,” he said with derision. “I want to take a look. With my own eyes.”

Scarborough was tempted to suggest that Payton might also want to use his own field glasses, which were hanging in their case over the front of his parka. Instead he handed them to him.

“No problem,” Scarborough said. “Give ’em back to Shevaun when you’re done.”

Bradley nodded to Scarborough in a way he interpreted as sympathetic. It made him feel appreciated. And glad he’d curbed his irritation.

They waited as Payton studied the trail. A minute or two later he let the glasses sink to his chest.

“This isn’t possible, it—” He suddenly interrupted himself. “Wait. Do either of you hear that noise?”

Scarborough did. It was a kind of high metallic buzz that seemed to drill through the blanketing rush of the wind from an unresolved distance. He glanced at Bradley. The inquisitive tilt of her head revealed she was listening carefully to the sound, trying to pinpoint its source. While the reverberant acoustics of their surroundings made that hard, Scarborough thought it was issuing from the direction of the notch.

Payton evidently thought the same. He brought the glasses back up, aimed them at the yawning, jagged scar in the wall of the pass.

“What the hell is this?” he said. His voice was shaky. An instant later, his hands were too. “Scarborough, do your job. Will you do your goddamned job and answer me?”

Scarborough stared at the notch. At first nothing caught his attention. Then an object darted out onto the sand. From a distance it seemed a mere speck. But it was coming on at an incredible speed, growing larger in his vision with a quickness that matched.