Tania tugged at both their sleeves and pulled them close. “My air processor is off. I don’t know how long I can breathe this air. We have to get to the towers.” Her voice came out steady, even confident, belying how she felt.

Pablo nodded once. He said something to Vanessa, who responded with a lengthy sentence.

God, Tania thought, if the Helios was affected, too … The thought pushed her toward an emotional cliff of sheer panic. It took all her will to pull back from it. All that mattered was reaching the aura towers. She could camp there if necessary while Pablo and Vanessa found another aircraft in Denver.

All of the sudden the two immunes jumped to their feet, guns drawn, pointed somewhere behind Tania. The tunnel mouth, she knew. Tania rolled to her knees so she could see. She started to rise and felt Pablo’s hand on her back, pushing her low. A flash of light above her, along with a deep whump sound she felt more than heard. A gunshot. He was shooting. At what?

Vanessa fired, too. A rapid pulse of white light like camera flashes. In that burst of illumination Tania saw their target. A subhuman, running on all fours toward them. Toward me, she thought. Could that be right? When the gunfire ended the creature was in shadow, Pablo’s flare behind somewhere on the ground behind her. Pablo fired again. How he could still see the thing she couldn’t fathom, but in the burst of light from his gun she saw a bullet hole appear on the left side of the sub’s forehead. Tania moved to her right to let the light from the flare pass her, just in time to see the creature collapse into an unmoving heap just a few meters away. One of its hands—a dirty, scarred thing with jagged fingernails—was outstretched toward where she’d been.

No, she thought. Not where I’d been. Where the object had been.

Vanessa’s cupped hands were on the side of her visor again. “Where’s your gun?” Then her hands went away, replaced by an ear pressed against the glass.

“I dropped it when the lights went out, into the water.” Tania searched the woman’s face for a reaction to that and saw nothing. The immune whipped her focus back to the tunnel mouth. Her lips were moving. Talking to Pablo again. The lack of sound from the outside wasn’t quite as terrifying as the absolute blackness had been just minutes before, but it was close.

With no gun to carry about, the task of carrying the alien object fell to Tania. Pablo emptied nonessential gear from the bag he’d left onshore and gestured for her to place the triangular mass within. She did so, then zipped up the bag, pausing only for a second to soak in those green angular filaments of light.

She hoisted the bag on one shoulder and saw Pablo was already moving. She followed, up the sloped tunnel through which they’d entered, leaving the shell ship behind them, perhaps forever. Tania tried to imagine recreational cavers exploring this place a hundred years from now. What would they make of the empty ship? The skeletons they’d find? She tried to picture the confusion on their faces if they searched hard enough and found her gun at the bottom of that river. This place would have to be marked, perhaps even made off-limits if the world ever recovered enough to worry about such things.

Ahead, Pablo had reached the first junction in the tunnel. He whipped his red flare in one direction and then the other. Then he whirled on her, shoulders up and hands turned out in a silent question: Which way?

Tania shrugged. How the hell should I—

Oh, shit. The map.

Stupidly she tapped away at the controls on her suit again. Of course this changed nothing. Her HUD was blank. No clean little 3-D trail marking their path, no reassuring display of her remaining air. Nothing. The electronics were fried. The caps would need to be replaced. Firmware, reloaded. Even then it might not work, and anyway it didn’t matter. It was entirely possible there was no repair capability left on Earth, much less someone with the knowledge to do the work. Like most complex things that broke, it would be tossed, and the scavengers tasked with finding a replacement. Good luck, on a suit like this.

Focus! she screamed at herself. Tania strode up to Pablo and pulled his head close again. “My suit’s off, I told you. No map!”

He opened his mouth, closed it, then shut his eyes in frustration. When he opened them, a bit of calm had returned to those eyes. “Try to remember,” he said patiently. He couldn’t cup his hands to channel his voice into her helmet, so he’d simply pressed his cheek against the glass. It worked well enough.

“I …” Tania paused. She simply couldn’t picture it. She hadn’t been paying attention, not beyond referring to the glowing line whenever necessary. She’d been relying on the computer to handle the task, and that, she supposed, was exactly what the Builder’s …

The thought hit her like a thunderclap. Puzzle pieces, slipping into place as if finally viewed from just the right angle.

Can we retrieve this without electronic aid?

Could we fetch the object in Ireland under the accelerated pressure of time?

In Belem, could we overcome the augmented warriors. Could we fight and win?

She didn’t know what Samantha had faced in Darwin, but it had sounded bad. And she couldn’t fathom to guess what Skyler would find in Africa. It would be tough, no doubt, and doubly so with the presence of Blackfield.

Maybe we’re just inmates, she thought. Earth our prison, and all this just a test of our mental facilities.

“Well?!” Pablo shouted into her helmet. There was no malice in his tone. No, the opposite was true. He’d no doubt mistaken her suddenly contemplative gaze and assumed she was recalling the map in her mind.

“It’s gone, Pablo. It’s gone.”

She half-expected him to swear, to fly into a rage. There was no basis for that; he’d been nothing but patient before. A kind, quiet man.

Sure enough, he just closed his eyes and nodded. Disappointment, frustration, yes, but also understanding. He looked like her own father had when she’d failed her first test in school. “You’ll have to try harder next time,” her father had simply said. She’d felt like a child then and she certainly felt the same way now, only here there was no “next time.”

Tania Sharma took a deep breath and forced all this from her mind. She was a scientist; she needed to think that way. The map was gone and so it was irrelevant. A data source that couldn’t be used. What else did she have? Tania glanced at the cave itself, first looking for anything she could remember. It was useless, though. The tunnels all blurred together.

Something on the ground caught her eye. She moved past Pablo and knelt down. There, in the space between two clumps of rock on the floor, was a partial footprint. A hint of boot tread, actually. Tania pointed at it. The man nodded, slowly at first and then a bit faster. He said something, and though she couldn’t hear it she thought he was chastising himself for not having thought of the same thing. Tania gave his arm a little squeeze and smiled at him. He didn’t smile back, but the corner of his mouth twitched and Tania thought that was good enough.

“Let’s go,” he mouthed.

Chapter Seventeen

Southern Chad

31.MAR.2285

Skyler pressed himself against the wall and waited for Ana to move in behind him.

He trained his rifle in rapid sharp movements on the likely places enemies would be. Alcoves on either side of the room, the corners to either side of the entryway, that dark Y-shaped passage that exited out the back with one path leading up and the other leading down.

When no subhumans presented themselves as fodder for his firearm, Skyler took in the details of the alien place. The walls were constructed of the same material as the towers, or so their appearance said. The now-familiar black surface that had no shine to it, interlaced with geometric grooves. The patterns were bigger here, though, and not as intricate, nor were they glowing from within.

The walls were not vertical, but instead slanted inward slightly. Whether on purpose or not, the effect left Skyler feeling like the place was about to collapse in on him.

The floor had a slight undulation to it, further upsetting his equilibrium. Individual hexagonal sections perhaps three meters across were themselves flat, but they were not all on the same plane. The slight variance made the floor look vaguely as if a gentle wave had run underneath and then frozen in place. The sections differed from the walls in a material sense, too. Black, of course, but textured, reminding Skyler of the spray-on coating that lined the cargo bed of many trucks.

The ceiling consisted of much smaller hexagonal tiles, black as night. All of the yellow light within the space came from a narrow, glowing band that marked the gap between floor and wall, illuminating everything from below.

Every few seconds, a warm breeze would push against him from within, then turn and pull inward again. It was impossible not to think the building breathed.

Movement to the right caught his attention. He’d been so transfixed on the architecture around him that he’d half forgotten about the mission, the danger. Ana had slipped inside and was in position directly across from him, crouched down on one knee and sweeping the alien room with her rifle as he had. He caught her eye and pointed at himself, then pointed forward. She nodded.

Skyler moved along the wall, rolling his feet to keep them silent. He checked the alcove across from him first, saw it to be a meter deep and empty, then he stepped out from the wall and spun around to look into the alcove next to him. Empty as well. He took a position in it and motioned for Ana to move up.

Once she’d taken the alcove across the room, he stepped out again and continued to the back wall. Outside he heard a sudden eruption of chatter among the subhumans who’d swarmed on their diversion, reminding him of the dingo packs that roamed the canyons south of Darwin. Sometimes in the night he could hear them fall upon some unsuspecting animal, even from as far away as the airport hangar.

He waited for a second, aiming toward the entrance and expecting the pack to return, but as quickly as it had arisen the sound died out. Skyler shared a nervous glance with Ana and continued to the back of the room.

A wide gap in the rear wall served as the only exit. The hallway split in a Y just a few meters in, one section diving downward at a steep slope and the other going up at an identical angle.

He paused as another unnerving waft of warm air pushed against him, stronger here in the narrow mouth of the hallway. The “breath” carried a faint chemical odor he couldn’t identify. As he waited for Ana he heard sounds, too. Barely audible, baffled by the layout of the building, no doubt, but there. Movement, chatter, and the underlying drone of some kind of machine.

Ana came to the wall on the hall’s opposite side and glanced at him.

“Up or down?” he whispered.

“Down,” she said, sounding only half sure of her quick answer.

As good a choice as any, he thought, and moved into the narrow space. Narrow compared to the room outside, but still spacious by human standards, he felt. Three meters across, wide enough for one of those hexagonal floor sections. The tunnel, like the room that fronted it, had the same undulating floor and sloped walls lit from below. The ceiling remained a narrow band of black, at least five meters above the floor. Skyler wondered for a moment what this might say about the Builders themselves. Were they twice our height? Perhaps walking on four crablike legs that spread out below them to support a heavy torso? He almost laughed at himself, for the thought conjured an image in his mind right out of some sensory shooting game.

Focus, focus. He mentally banished the visual. Let Tania and the other scientists theorize.

“Careful!” Ana hissed.

Skyler froze. In the gap where two hexagonal tiles met was a chute that went straight down into inky darkness. The toe of his boot dangled over the space, and his next step would have taken him in. Slowly he stepped backward and knelt. From a meter away, with his focus on the hallway as a whole, the floor looked entirely solid. But if he stared at the section while standing right next to it the gap became obvious. The illusory effect was nearly perfect. He swallowed, studying the rest of the slanted tunnel before him, to no avail. It was impossible to tell one section from another until standing right over it. He wondered how many subhumans had slipped into the pit, and if the bottom was full of their broken bodies. The hazard made one thing clear: He’d have to slow down drastically or risk falling in.

And yet any minute now the subhumans outside would likely give up on the diversion outside and return to guarding the doors, assuming that was what they’d been doing in the first place. It certainly seemed to be the case.

Skyler sat down, set his gun on the floor, and started to untie his boots.

Ana glared at him from across the hall. She kept her voice a whisper. “What are you doing?”

Better to show her, he decided. He pulled one boot off and tipped it over, placing his other hand beneath it. Yellow sand spilled out into a neat pile on his palm. More than he’d hoped for, in fact. He stood, centered himself in the hallway, and tossed the handful of sand like a bowler in a cricket match.

The particles flew out in a cone before him and made their own whisper as they hit the floor. Thanks to the slope of the hallway, the sand rolled and bounced many meters ahead, coating the hexagonal tiles and the gaps between, except in two other places where darkness remained.

“There,” he said, “and there.” Skyler emptied his other boot and shoved the handful of sand into one of his pockets. While he relaced the long black shoestrings, Ana sat down and repeated his action. She thrust two handfuls of sand into her jacket and grinned at him when they were both ready to go again.

The tunnel evened out after twenty meters. By now the sounds of subhumans outside had vanished completely. Either they’d given up on the burning truck, or Skyler and Ana were simply too far inside now to hear them. Skyler hoped for the latter, or else getting out would be a bloodbath.