Linda reached up and grabbed Khalid's offered hand, fighting back a wave of revulsion. At his touch, she almost pulled back, but his grip, dry and warm in her palm, held her tight. Reluctantly, she allowed herself to be hauled up the last yard of the rockfall. She risked a glance back down the cascade of boulders they had just climbed. Lit by the ubiquitous fungus, the cavern floor was hundreds of yards below them.

"I was right," Khalid said, pointing to the crack in the wall at the top of the rockfall. "Look. It is a fault-line crack. And it goes up." He turned to her with a huge grin. "Do you feel it? The wind?"

She felt a soft brushing of air across her cheek as the crack drew a breeze down its dark throat, almost like it was trying to suck them in, the draw of air whistling down the passage away from them. "It seems promising." She forced the corners of her lips up.

In answer, his grin became even wider. She stared up into his eyes, two black holes in this light. As he turned, she was tempted to twist free and rush down the rock face. But her feet followed Khalid into the V-shaped crack in the rock.

After a few yards, Khalid clicked on his helmet lamp. No fungus grew on these slanted walls. His beam of light thrust forward, ripping into the virgin darkness. She unharnessed her own hand lantern, twisting it to a diffuse setting to wash broadly across the rock.

Walls spread to either side like wings of stone. The roof far above their heads looked like a single slab of rock tilted and resting precariously in place. So fragile, it seemed even a loud noise might shake it loose, crushing them under miles of rock.

"I think this is a relatively new formation," Khalid said. "From a geologic standpoint, that is. Maybe only a thousand years or so. The rock"-he patted the wall on his right-"is not as water-worn as the rock in the previous cavern. Notice how sharp the rock is, like it was sliced with a knife. A recent seismic event must have created this crack."

"There's no fungus either," she mumbled.

"What?"

She waved her light on the walls. "No fungus here. I think if it was a million-year-old crack the fungus would have invaded here too."

He nodded. "True."

"We need to be sure that wherever we make camp tonight there's no fungus nearby. Or if there is, that I check it first," she said. She found talking seemed to push back the clinging terror around her heart. "During the rest breaks, I've analyzed several samples of the fungus. They're not all the same. I'm pretty sure that most of this glowing fungus is safe. The predatory species, though, has a distinct hyphae structure. So we need to watch out for it."

"Of course. We must be more wary." He turned forward.

She wanted to continue talking, to keep herself distracted from the thought that she was following a cold-blooded killer. "How did you get picked for this mission? Was it because of your geology background, or were you always a…" She almost said "terrorist," but she allowed the word to die in her throat.

"I'm not a geologist," he said. "I was assigned this mission two years ago and was taught as much geology as I could learn in that time. Not only to impersonate Khalid, but also to better understand what I might discover down here. I had plenty of time to study as I recuperated from my plastic surgery."

Her mind spun with his revelation. "You're not the real Khalid Najmon?"

He helped her over a blockage of tumbled stone. "I already looked much like the original Khalid. That's why I was chosen. But my superiors are thorough. They wanted a more exact match."

She watched his back as he climbed ahead of her, beginning to understand the depth of his drive, his fanaticism. "What happened to the real Khalid?"

He turned his dark eyes toward her, his gaze disapproving, as if her question were foolish.

"What is your real name?"

He ignored her question and turned away. "There's light up ahead."

She sidled next to him to look ahead, suddenly hopeful. Maybe a way out? The tunnel here widened to the size of a small cavern. A glow emanated around a turn in the tunnel. The characteristic green light left no doubt what lay ahead. "Fungus," she said tiredly.

He nodded. "But listen."

Now that he mentioned it, she could hear it too. A low roaring. She recognized the sound from her grandfather's home outside of Quebec City. "Sounds like a waterfall."

"Yes, I think so. But it's getting late. And with fungus ahead, we should make camp here. We can strike out in the morning for the falls."

She nodded. She too had no desire to battle another attack by the predatory mold, but she had been dreading this moment as well. Camping. Spending the first night with the man she now knew as a murderer.

Suddenly a yell echoed from the tunnel ahead. Startled, Linda involuntarily stepped closer to Khalid. Someone calling. It was from far away, but it was human!

"Jason! Where the hell are you?"

Gosh, Jason thought, can't a guy get a little privacy? Zippering his pants, he stepped back around the stalagmite into view. "I just needed to take a leak," he called to Dr. Blakely. "I've been holding it all day."

The doctor hurried over to him, still dripping from his swim, his eyebrows knit with anger. "Don't ever do that again!"

"What?"

"Run off like that."

"I was only over there." Jason pointed at his rest station.

"I don't care. There are all sorts of hazards around here." Blakely's face relaxed, but his breathing was still raspy. "Listen, Jason, we need to be careful. Stick together."

"All right. I didn't mean to…"

"It's fine. Now let's see about that bump on your noggin."

Dragging his feet, Jason crossed to the small boulder and sat. With a grimace, he let Blakely clean his wound. It wasn't too bad when he flushed the wound. Heck, it almost felt good. He relaxed, closing his eyes. Suddenly his forehead stung as if it were on fire. "Owww!"

"Oh, quit fidgeting. It's only a little iodine."

"It burns."

"That's good. That means it's working." Blakely strapped a sticky bandage over the cut. Then he sat back, seeming to admire his handiwork. "We'll need to change this twice a day."

Jason rolled his eyes. Great.

Blakely crossed to fish through the collected salvage from the boat. "Are you hungry?"

"No. I'm fine. Unless you have one of those chocolate bars."

Blakely hauled out the box that held the food and cracked it open. He reached in and pulled out a foil-wrapped bar.

Jason's eyes widened. He held out a hand.

The doctor split the bar into quarters, then passed him a single section. "We're going to have to strictly ration our supplies."

He accepted his share with a frown. Man, this sucked. "So how do we get back up?"

"We don't. We have no flashlights."

"So what do we do?"

"We wait. A day or so. Someone will find us."

Jason knew a lie when he heard one, but he kept his mouth closed. The doctor had enough on his mind, and Jason didn't want to be a bother.

Slumping on the rock, he noticed a familiar red bag. "Hey, my gym bag! You saved it. Thanks!" Scooting over to his bag, he opened it up and pawed through it. Still here!

He pulled out his Nintendo game and sat back on his heels with a sigh. He thumbed on the power button, and in a few seconds, a familiar theme song jingled from the game. "Cool!"

Jason leaned back against a stalagmite and attended to his game. At least he would have something to do while they waited. Immersed in the world of Nintendo, it was almost like he was back home. By now his mother was usually complaining about the noise from his Game Boy. Sighing, he plunged his character into level twelve.

"Jason, could you turn that off," Blakely said, standing up. "The noise."

Jason grinned. Just like his mother. What was it with grown-ups anyway?

"Please, Jason, hurry." There was a note of urgency in his voice.

He clicked off the game and stood up, crossing closer to Blakely. "What-"

"Shhh! I thought I heard something."

Jason held his breath, picturing another of those creatures sneaking up on them. He shifted farther behind the doctor. They waited for several tense heartbeats. It was difficult to hear with the waterfall crashing so close. Straining with so much churning water nearby was beginning to make his ears ring. He swallowed hard, his mouth dry. Maybe the doctor had just thought he heard something. Like one of those desert mirages, but with sound. He sure as heck hoped so.

Blakely shook his head. "I don't know-"

"Hellooo!" The call echoed through the cavern, causing both of them to jump.

Blakely looked at Jason. "Someone's out there! I can't believe it!"

Jason watched as Blakely climbed on top of a boulder. It took the old man a few tries to boost up on top. Jason clambered deftly up next to him. "Who do you think it is?"

"I don't know, but let's find out." Blakely cupped his hands over his mouth and yelled, "We're over here! By the foot of the waterfall!"

Jason listened for a reply. Nothing for several heart-beats, then an answer: "We're coming! Stay put!"

"I told you someone would find us. I told you." Blakely suddenly sounded exhausted and wheezy as he scooted from the boulder.

Jason watched the doctor slump to his knees beside the rock. Something was wrong.

Jason hopped down and crossed to the doctor. Blakely coughed raggedly, then slipped to his side and collapsed.

"Dr. Blakely!" Jason tugged on his arm. He didn't respond.

Jason's heart seized in his throat. He searched around him, desperate, his hands shaking. Jason darted to the boulder top and screamed at the shadows, "Help!"

Linda hurried to catch up with Khalid, her pack dangling from one shoulder. She stared across the cavern. "That sounded like Ashley's son."