"I still don't know what I'm looking at."

Gage sighed, clearly disappointed with her powers of observation.

"Hey, I was never an Eagle Scout," she said. "You're going to have to spell it out for me."

His hands dropped away. "This is the same view we had from on top of that mercury mine the other night. Remember with the night-vision goggles?" He pointed at something straight in front of them. "I was looking right at that mesa. At that same stand of mesquite trees, in fact."

She turned around. "I was stuck in the cave with all the bats bats. You were the one traipsing around with the high-tech toys."

"Okay, point is, what if Dylan was out here taking pictures and he saw the same thing I saw? Maybe he got curious later and decided to drive out there and take a look."

"You're talking about the vanishing SUV?"

"Or whatever it was." Gage's attention was fixed on the horizon now. He shrugged out of the backpack he always carried and unzipped it, then pulled out a pair of binoculars. "You see his black Explorer down there?"

"I can hardly see anything. It's getting dark."

"I'm thinking maybe he left the dig site to go get a beer, like he told Rohit, then decided to take a little detour first to do some exploring."

The idea made Kelsey's stomach knot. She envisioned one of her students down in that valley, near where that girl had been dragged from her car and shot. She scanned the horizon, desperate now for any sign of the SUV. Would Dylan really have driven down there?

Gage pa.s.sed her the binoculars. "I don't see jack."

"What about the night goggles?"

"Not dark enough yet."

Kelsey peered through the binoculars. The light was terrible. If his car was was out there, would she even be able to spot it? She saw a clump of mesquite trees. A twisted oak. A dip in the landscape. More mesquite. out there, would she even be able to spot it? She saw a clump of mesquite trees. A twisted oak. A dip in the landscape. More mesquite.

And then she spied something. Black. Rectangular. Poking out from behind a clump of scrub brush.

"Oh, G.o.d."

"What is it?" Gage asked.

"I'm not sure. Probably nothing." But the knot in her stomach tightened because she knew she was wrong. It was was something. Something that didn't belong down there. something. Something that didn't belong down there.

Nature doesn't like straight lines.

"Oh G.o.d, Gage." She looked up at him. "I think I might have found his Explorer."

"MAYBE IT'S JUST a stalled car." a stalled car."

Gage turned to look at her as the pickup b.u.mped over ruts in the primitive highway. He didn't say anything. He couldn't. He didn't want to encourage her to get her hopes up.

"Or maybe he had a flat." Kelsey stared straight ahead through the windshield as the headlights lit up the muddy road. "He'd stay with his vehicle, right? I mean, if he couldn't get a cell signal. That's what they say. If you're stranded in the desert, don't don't leave your car." leave your car."

Her voice was firm, confident. As if saying it with enough conviction would make it reality.

Gage was pretty sure he knew the kind of reality they were going to find when they drove up on Dylan's Explorer. It wasn't going to be pretty. And no matter how many skeletons Kelsey had pulled from the ground, it was going to hurt her. It was different when it was someone you knew.

"Try my cell again." Gage fished his phone from the cup holder and handed it to her, mainly as a distraction. "Maybe we'll luck out, get a signal. Sattler can't be doing anything tonight, right?"

Like a robot, Kelsey dialed the numbers. Again, no dice. She let the phone drop into her lap and just stared out the window.

She felt responsible, and Gage ached for her. He knew that feeling well, and it sucked. And to make things worse, he knew this was a bad idea. What they should have done was double back for the sat phone and call the sheriff out here. But Gage had seen the look on Kelsey's face after she'd spotted the SUV. No amount of persuasion would have kept her away. If Dylan was out here alive, he probably needed help, and Sattler wasn't known for his quick response time.

Gage tore his gaze away from Kelsey and focused on driving. This was a c.r.a.ppy road under normal conditions, but with the rain earlier it had become a mud pit. The highway jogged east and Gage slowed as he pulled off. The headlight beams bounced along the pitted terrain, lighting up cacti and rocks and scraggly bushes. He tried to drive by feel, letting his tires find the natural path that had been carved out by repeated use. This was the most basic kind of road-no pavement, not even gravel, just a strip of land made bald as people sought out the shortest distance between point A and point B.

The headlights flashed over a clump of mesquite trees. He spotted an odd-shaped boulder that looked familiar. This was the spot.

But no black Ford Explorer.

Gage rolled to a stop beneath a gnarled oak tree and parked. He reached into the back of the cab and retrieved his rucksack, which contained a collection of weaponry, including his backup gun. He tucked the pistol into the waistband of his jeans as Kelsey watched him, wide-eyed.

"When I get out, scoot into the driver's seat," he said. She had her radio clipped to her belt alongside her gun, and he reached over her to switch it on. "Keep the engine running. If anyone approaches you, take off."

"But what about you?"

"Get your Ruger ready. And don't be afraid to use it if you feel threatened. You got that?"

"No. I'm coming with you."

"I need you to stay in the truck," he said. "It's not safe for you to-" She pushed open the door and got out. "G.o.dd.a.m.n it, Kelsey!"

She stalked right over to the stand of mesquite. She did a complete turn and gestured at the trees. "It was just here a minute ago. I saw saw it. How could it disappear like that?" it. How could it disappear like that?"

Gage scanned the area for threats as he joined her beside the trees. He'd never met a woman who was so bullheaded.

"I need you back in the truck while I look around."

She turned to face him. "It was here here. Right near this weird boulder. I saw saw a black SUV sticking out from these trees. You saw it, too." Her eyes looked slightly wild now as she glanced around in the dimness. "Am I going crazy here? Is this the Bermuda Triangle?" a black SUV sticking out from these trees. You saw it, too." Her eyes looked slightly wild now as she glanced around in the dimness. "Am I going crazy here? Is this the Bermuda Triangle?"

"No." Gage wasn't sure what it was. But he had a hunch the explanation was frighteningly simple.

Giving up on getting her back in the pickup, he pulled her closer to the big rock. "Stay here. And be quiet a second."

She fell silent, and Gage took a full minute to absorb his surroundings. To their west was a low mesa. Less than a mile south, the river. The valley rose gently to their north until it b.u.t.ted up against the limestone cliffs that marked the southwest boundary of the dig site.

Gage looked west, where the sun had disappeared behind the mesa. Night was falling faster than usual because of the cloud cover, and in ten minutes it would be nearly impossible to see.

"Stay here," he repeated, squeezing Kelsey's shoulder to reinforce the command. Then he moved off toward the boulder.

The rain had stopped, but the air felt saturated, and he knew it was going to be one of those on-again off-again storm nights. Thunder rumbled low to the north, as if echoing his thoughts. Wind rustled through the scrub brush. An animal snarled in the distance, but he heard not a single sound that resembled a motor.

His eyes had adjusted, and he could still see somewhat, despite the coming darkness. He walked all the way around the rock, looking for any sign of Dylan or his SUV, half expecting to stumble over the guy's bullet-riddled body. He circled the clump of trees. He even pulled out a penlight and combed the ground around them.

Fresh tire tracks, leading back toward the highway. But no Dylan.

Gage stood there, running through scenarios. Dylan could have been out here changing a tire, then left, just as they'd been coming to his rescue. But, if so, why hadn't they pa.s.sed him on his way back to camp?

The kid could have heard them coming and been afraid for some reason and driven away. Maybe he'd been injured by someone or something and had just now made it back to his vehicle.

He could be dead, and someone could have taken his SUV.

Gage made his way back to Kelsey, letting his flashlight beam trail over the ground.

"Gage," she hissed. "Come look at this."

And that's when he spotted it.

Camouflage netting tossed carelessly over some bushes. Only it wasn't careless at all. And suddenly everything fit together-the traffic, the shootings, the disappearing vehicles. He crouched down and lifted a corner of the netting, revealing a small metal grate.

"Gage, you have to-oh!"

He whirled around. "Kelsey?"

She didn't answer.

Seven.

Kelsey blinked up at the blackness. She couldn't see. She couldn't breathe. She tried to sit up but it felt like sandbags were piled on top of her chest.

"Kelsey, answer me, d.a.m.n it! Where are you?"

She opened her mouth to talk but all that came out was a strangled cough.

"Kelsey?"

His voice was moving farther away, and she summoned every ounce of strength to turn onto her side and push herself up on an elbow. "Here," she wheezed.

He was beside her in a heartbeat. His hands were all over her-her arms, her legs, her face.

"Are you okay? Did you break anything?"

"I hit my... solar plexus... knocked the wind out." She was getting her breath back but she still couldn't see, and she clung to Gage's arms. A flashlight blinked on.

"Is anything broken?" He shined the light in her face and she squinted. "You fell about ten feet."

"I'm fine." She experimented, moving her legs, her arms. "My coccyx hurts a little, but-"

"Your what?"

"My tailbone. I'm fine otherwise."

The light blinked off, and his quiet laughter surrounded her. At some point he'd put his arms around her, and she leaned into him now, absorbing his heat as she tried to catch her breath.

"Guess you're all right if you still know your anatomy." He eased her away. "Can you stand up, you think?"

He helped her to her feet. She felt unsteady so she held onto his arm.

She glanced around. The air felt cool and damp, but she still couldn't see anything. "What is this hole?"

"Not a hole. A tunnel."

She blinked into the darkness and turned around. There seemed to be more light behind her, a very faint glow.

"A tunnel," she repeated. "You mean like a mine shaft? I saw an opening. It's probably a mercury mine."

"It's not. Maybe it was at one time but that's not what it is now. It's a border tunnel." The light flashed on again, and he directed it over the walls around them.

"Oh, my gosh," she murmured.

The pa.s.sageway was wide and tall. They both could have stretched their arms out and not touched the sides. And unlike the mine shaft near the dig site, these walls were made of cinder blocks.

"They have these between San Diego and Tijuana," Gage said. "But I've never heard of any in the middle of nowhere like this. And I've never heard of any this big."

He switched off the light and began guiding her toward the dimly lit end, which must be the way out. She'd thought it was dark outside, but this was an entirely different level of blackness.

"This is huge," she said. "Big enough to drive a truck through."

"From the smell of it someone has."

She sniffed the air and realized how else this place was different from the mine shaft. Instead of guano, she smelled gasoline fumes.

Gage halted.

"What?"

"Someone's coming."

She heard it then, the faint rumble of a truck. It was coming from the direction of the glow. From outside.

"Where do we go?" she yelped.

"Don't panic." And then he was towing her into the blackness, deeper into the tunnel.

She resisted. "But we don't know what's in there."

He pulled her against the wall and moved faster. "I'm feeling for a door. A turn. Anything where we can duck out of sight."

The rumble grew louder until it was nearly a roar. They were running now, and her foot caught on something as she struggled to keep up.