A hand on her back, Vanessa’s, pulled her. Tania glanced behind her to see the woman’s face in the shifting light. Her eyes were cast upward at Pablo, her mouth a tight line. Tania felt the now familiar whump whump of gunfire coming from above. Vanessa was saying something, urging her backward. Tania went, letting the woman pull her back the way they’d come. Ten meters, maybe more, before she shoved Tania to one side of the tunnel and brought her gun up.

Tania looked at the slope. The red light grew as Pablo came back down. First she saw his feet, moving backward down the incline. Then his legs, torso. All the while bright flashes of white light erupted from ahead of him. His gun. She thought there must be a lot of subhumans up there because he kept shooting. Soon enough his whole body was visible. He took a knee at the bottom of the ramp and quickly reloaded. As he did so, a subhuman—muscular, compact—raced past him. It ran straight toward Tania. Silhouetted against the red flare it looked like an ape, except only the head and chin had hair.

Vanessa shot the former human twice in the chest and it crumpled to a heap a few meters in front of Tania. The gunshots were so close she could hear them through her helmet, like the sound of snapping fingers. Tania hardly had time to feel helpless when she saw Pablo’s flare move again. He’d tossed it aside so he could aim with both hands. A subhuman body rolled down the incline before him, forcing him to step aside. Another came down, running on all fours, again trying to slip past him rather than fight.

Pablo turned to shoot it as it passed, putting his back to the narrow side tunnel. He fired into the creature’s side. She saw it react as if merely swatted at. One hand went to cover the wound, and the other continued to act as a leg as the creature rushed toward them. Vanessa finished it off.

Pablo must have told her to retreat, and shoot any that got past, Tania realized.

A shape, a blur, exploded out from the side tunnel. It leapt onto Pablo’s back and the two went down in a cloud of dust. Kicking. Flailing limbs. A flash of gunfire.

Tania screamed, pointless even if anyone could hear her. She heard more gunfire from her left. Vanessa, firing into that confused mess? Too risky! Tania moved to stop her and realized she wasn’t shooting toward Pablo: She was shooting behind them. She glanced back to see, but the tunnel was pitch-black. Each time she fired a small spark would erupt off the rocky walls behind them, giving Tania a brief glimpse of shapes moving toward them.

Trapped. Oh God.

The light Pablo had dropped faltered. Dirt, or rock, kicked on top of it. Tania dropped the pack that carried the alien object and rushed forward without another thought. Churned dirt and dust filled the tunnel now, giving her only a few meters of visibility. She saw movement. Feet, kicking—no, convulsing. Booted feet, Pablo’s. The creature was on top of him, swinging wildly down where his head must be.

Her combat training kicked in. She kicked, and though she’d taken the correct stance her suit made the motion stiff, awkward. She’d aimed for the thing’s head but hit it in the back of the neck. No matter, she had its attention. Tania followed up with a punch that landed perfectly on the sub’s throat. She felt the Adam’s apple shift under her blow, even through the thick glove of her suit.

The creature fell back, gasping, clutching at its throat. Tania stomped down on its abdomen, forcing the air out of it. It might not die, but it would be down for a while, so she shifted to Pablo. His face was a bloody mess, and he wasn’t moving. His eyes were open, staring upward.

No. No!

She slipped her hands under him, lifting him by the armpits and dragging his heavy, limp form. Pablo’s boots scraped two horrible trails along the floor of the tunnel. Subhuman bodies littered the ground, their blood mixing with the churned dirt. Tania could only see a meter in any direction, so thick with dust the air had become. It probably tasted dry and tinged with brass, but Tania would gladly breathe it right now if she could. The air in her suit wouldn’t last much longer, of this she had no doubt.

She pulled Pablo’s body around a fallen subhuman. All the while Vanessa kept shooting, ahead and behind. The half-buried red flare sputtered one final gasp and then the tunnel plunged into absolute darkness. With the black came a strange serenity. Tania groped around until she found Pablo’s neck. She felt no pulse, but couldn’t be sure if she would feel it through the gloves of her suit. So she pressed her fingers to her own neck.

The vein below her skin pounded against her gloved fingers.

Pablo was dead.

Tania slumped forward, clutching the quiet man to her, not caring now if her own supply of oxygen would run out as she wept. Another life, another good person, sacrificed to whatever these goddamn aliens wanted. She wanted to take that triangular slab of exotic material and throw it into the cold dark waters below. Let all the subhumans jump in after it. If they wanted it so badly, maybe they should have it.

Vanessa lit the extra flare and Tania found herself staring into Pablo’s eyes. His face was a horrific mess of blood and deep gashes, but the eyes … his eyes were perfect. Strong, intelligent, calm.

No. No, she couldn’t quit. If everyone else succeeded, then all this would be for nothing, and she wouldn’t let that happen. She wouldn’t let this man’s death be for nothing. With one gloved hand, Tania reached out and drew his eyelids closed.

She felt a hand on her shoulder. A second later Vanessa collapsed on the ground next to her and fell over her friend’s body. The anguish on her face knew no equal, Tania thought, and though it hurt to admit it, she felt glad in that moment that she couldn’t hear the woman’s cries.

Tania stood then. Something insider her ignited, brighter than the flare, brighter than the fucking sun.

She picked up the bag that held the alien object and hurled it toward the slope in the hallway.

A second later two more subs came down the incline. Instead of rushing at her, they fell on the bag, clawing at it to reach the artifact within. Tania picked up Vanessa’s gun and walked calmly forward. In the hazy red light it became easy to forget these beings had once been human. She put a single bullet into their heads from point-blank range, ignoring the sick way they convulsed, the fine spray of blood that dotted the glass of her helmet. Then she leaned against the wall and waited for the next. She shot that one, too. When the fourth came the gun clicked empty. Tania tossed it aside and threw her arms around the creature’s neck, covering its mouth and nose as she’d been trained to do. The animal—that’s what it was, an animal—began to claw violently at her arms but she held on until the body went slack against her. Tania let go. The body collapsed at her feet.

She stepped back again and waited, but no more came. Then something brushed her arm and Tania wheeled, lashed out, only to see Vanessa next to her. The woman raised her hands defensively until Tania relented.

The tears Vanessa had cried for Pablo ran in two vertical streaks down her dust-coated skin. Yet her expression held no sign of grief now. She reached out to Tania, grabbed her helmet, and twisted.

So this is it, Tania thought. We kill ourselves, like Jake did, rather than let them get us.

There was no hiss of air when the seal broke and the helmet came away. Tania ignored that and sucked in a breath of gritty air. She almost coughed, but somehow managed to choke it down. “I should have saved a bullet for each of us, I guess,” Tania said.

“Don’t say that,” the woman replied. “We need to run now. Can you do it?”

“My helmet,” Tania said numbly. “You—”

“The suit is torn,” Vanessa said. She lifted one of Tania’s arms and showed her. The material had been raked to shreds by the subhuman she’d strangled. “Take this knife. I’ll carry the … thing.”

“It’s hopeless,” Tania said, watching the immune shrug the bag that held the alien artifact onto her back. Her head pounded; whether it was from the near asphyxiation or the tainted air she now breathed, she had no idea.

Vanessa gripped her by the shoulder and growled her words. “It’s not. We’re going. The towers aren’t far, Tania. We’ll fight our way and finish this for him. Do you understand?”

Tania stammered.

“Go!”

She went. Up the slope, knife held before her pointed downward from her clenched fist, a style that allowed her to punch and slice rather than risk burying the knife into something and losing it. By the time she reached the top of the incline her head pounded. SUBS, already working its way into her brain. The first symptom, the headache, she knew lasted anywhere from one minute to as much as ten. Ten minutes, if she was lucky, to get to the aura and suppress the virus with nothing more than a pain in the skull to deal with. She’d be like Karl, popping painkillers with every meal, forever. If the disease progressed beyond that, she’d likely be killed on the spot by the collapse of her mind. If she survived, Vanessa would either kill her or leave her here in the wilderness.

The immune still held the flare, running a few paces behind Tania. The red light’s jerky motion made Tania’s own shadow sway, grow, and shrink in front of her as if she were trying to catch up to a demon.

Her head felt like it had been clamped in a vise. Vision began to blur. She stumbled, righted herself just as the tunnel turned and angled down, then up. Another turn. Something was running toward her. For an instant she thought it was a dog or wolf, until she saw the human—vaguely human—face. It was going to run past her, again going for the artifact. Tania struggled against the crushing force inside her head and dove right as the creature passed her. She knocked the thing from its gallop stance, for it weighed almost nothing, and pinned it against the wall, lashing her fist across its throat at the same time. A sharp black line appeared across the throat and fluid began to spill out.

Good enough, she thought, and ran on, using the brightness and motion of the light behind her to make sure Vanessa was still with her.

Light ahead. The vaguest gray highlights on one side of the tunnel. A flashlight?

No, she realized. Sunlight, glinting off the rock. “Almost there!” she shouted. The woman behind her made no response, but Tania could hear the pace of her footfalls increase.

The entrance to the cave was a glowing white oval, so bright it blinded her for a moment. When her vision returned, Tania took in the expansive space that marked the cave’s entrance. She half-expected to see a crowd of subhumans standing there, waiting to ambush them. The room, however, was empty.

“Catch your breath,” Vanessa said. “We should be in the aura now.”

Tania hadn’t realized it until then, but the headache had dwindled back to something manageable. Still, she wanted nothing more at that moment than to get back to their aircraft and find a packet of ibuprofen. The first dose of many to come, she thought bitterly.

Pablo’s motionless face rose unbidden to her mind, dispelling the thought. Popping some pills was nothing compared to the sacrifice he’d made. Tania swallowed, accepting the pain as an eternal reminder that she still lived.

Vanessa stuffed the flare into a pile of dirt, killing its brilliant red light. Tania met her gaze and held it. She wanted to say something, anything, but no words came. The other woman broke eye contact first and glanced back down the tunnel through which they’d fled. Her lips moved in a silent goodbye, and one more tear rolled down a cheek that had seen too many already. She drew her arm across her face and let out a sharp breath. “He didn’t talk much.” Her voice was wistful. “Still, I felt like I knew him better than anyone.”

“I’m sorry,” Tania managed to say. The words sounded feeble, but the other woman nodded.

“Let’s go,” she said, “before the grief catches up with me.”

Tania glanced down at the bloody knife in her hand, tightened her grip on it, and started up the pile of debris that served as a ramp to the mouth of the cave. Her now-permanent headache began to flare again, forcing her to squint and hold up one hand to block the brightness of the daylight that spilled in.

Her headache grew. It is the brightness, isn’t it?

Another explanation came to mind, along with a cold revelation. Tania began to tremble all over. “Something’s wrong,” she said, her voice a miserable, shaky mess.

Vanessa called up from behind. “What is it? Do you see something?”

At the mouth of the cave Tania froze, and heard Skyler’s voice in her head—the last words he’d said before leaving Ireland. “There’s a bunch of aura towers coming back.…”

To the south, Tania could see the last of the emerald towers vanish into the tree line, headed for Belem.

No. Half should have stayed. Like Ireland and Belem. Why change the rules now, you bastards?

She dropped to her knees, watching the source of the aura disappear. She would die here, or become something … less. There was no way to scrub the air inside the Helios.

The teeth that had wrapped around her skull bit down.

Chapter Twenty

Southern Chad

31.MAR.2285

A violent wind roused Russell Blackfield from his fitful sleep.

The walls of his little prison shook with the force of the gust, and despite the closed doors a fine spray of powdery sand whipped in and coated everything. The winds outside dwindled as he became coherent.

He had no idea how long he’d been out. A wave of exhaustion had come upon him back in the aircraft. Lack of food, probably. Or depression. Whatever, the sleep had helped. He felt almost himself again.

He tried to move, only to find his hands were cuffed together, the chain going up and over a metal bar above his head. Some sort of closet, he guessed. The bar was thin but looked pretty solid. Two bolts held it to the wall at either end.

While he estimated his depleted strength versus those bolts, an alarm within his helmet caught his attention. It had been there since he’d woke, he realized, but only then did it occur to him that it mattered.