He asked again. "What is it?"

She rolled into a seated position, cradling the large shell in her lap. "If it's what I think it is…" She shook her head and placed a hand on his knee. "If it wasn't for your insistence that we stay a little longer, I may have missed it."

Her hand was a burning ember on his knee. He fought against pulling her into a hard embrace. A tightening in the crotch of his coveralls protested his restraint. "What's so special about an empty shell?" he asked in a strained voice.

Before she could answer, voices intruded.

"I'm telling you, the damned skeeter bit worse than a snake with broken fangs."

Ben spotted Khalid and Linda crouched by the shore of the pond. He noticed Linda slip her hand from the geologist's knee just as they rounded the rocky escarpment. Ben raised an eyebrow.

Ashley cleared her throat, announcing their presence. "Linda," she said as she approached, "Ben was just bitten by an insect that looks a lot like a mosquito. We wanted your opinion."

"Oh, sure, no problem. Did you catch one?"

"Well, kind of," he said, pointing to the smashed bug still smeared on his forearm.

She smiled, taking his forearm in her hands and rotating it into the light. "You didn't leave me much to go on." She leaned in closer. "I can't say for sure. There are hundreds of species of blood-hungry midges, flies, and mosquitoes. This could be anything." She released his arm.

"I was curious," Ashley said. "Ben told me there are seldom any biting insects in caves."

Linda scrunched up her eyebrows. "That makes sense. What would they feed on? No warm-blooded species down here." She shook her head. "They must gain sustenance in some other manner, but this individual was taking advantage of a new source for lunch." She shrugged. "These caverns just get more and more curious."

She clasped one arm around a large shell. "Look at this, for instance." She held up the shell for Ashley and Ben to examine. "Do you recognize this?"

Ashley took it from her and held it up, rotating it to view it from all angles and running a hand along its spiral loop. "Looks like a mollusk shell, but I'm unfamiliar with the species. Besides, you're the biologist."

"And you're the archaeologist. If it wasn't for my study of evolutionary biology, I wouldn't have recognized it."

"Well, what do you think it is?" Ben asked, lifting the shell into his hands, curious what all the commotion was about.

"It's the shell from an ammonite, a predatory squid," Linda said. "Species Maorites densicostatus."

"What?" Ashley snatched the shell back from Ben. She examined it again with keener interest, now holding it like it was the finest porcelain. "That's impossible. This is an actual shell. Not a fossil."

Ben stared at his empty hands. "What's the big deal? What's so bloody exciting about it anyway?"

Both women ignored him. "Are you sure?" Ashley asked. "Paleobiology was not a specialty of mine."

"Yes," Linda said. "Look here, at these striations. No modern mollusk has this conformation. And look at the chambering inside. Only one species has this unique shell. Definitely an ammonite."

Ashley leaned in closer. "But what's it doing here? Ammonites died out with the dinosaurs at the end of the Cretaceous period. This is an old shell, but I don't believe it dates back sixty-five million years."

"Let me take a look," Ben said, lifting the shell. "Many caves have preserved fossils, protected from the weather. Maybe this shell is just well preserved."

Linda nodded. "Perhaps. But before the expedition, in preparation for the trip, I read up on Antarctica's wildlife. On Seymour Island not far from here, scientists discovered many ammonite fossils. Remains that dated later than the Cretaceous extinction."

"Cretaceous extinction?" Ben asked. "What're you talking about?"

Ashley answered, "About 65 million years ago, at the end of the Cretaceous period, a great cataclysm wiped out huge numbers of species, including the dinosaurs. Some researchers theorized a massive asteroid struck the earth at that time, blowing up clouds of dust that blocked the sun and chilled the planet."

"Right," Linda added. "And the paleontologists studying Antarctica now believe that Antarctica's polar vortex may have stirred the winds enough to keep the asteroid's sky-darkening particles clear of this area, sparing this continent the great extinction."

Ben interrupted. "That's all old history. So these snails survived longer than anyone thought. So what? I mean-"

"Linda!" Khalid called. He had wandered off and knelt by the edge of the pond. "Here's another shell." He reached into the water, immersing his arm almost to his shoulder. "I can't reach… wait, no… there… I got it." He pulled his drenched arm out, his hand clasped around a shell larger than the first one. He straightened up, holding the shell above his head like a trophy.

Ben shook his head. Showing off big-time, he thought. He opened his mouth to make a comment when suddenly, from the shell, a flurry of thrashing tentacles sprouted. Linda gasped.

The tentacles latched onto Khalid's arm.

Khalid tried to shove the squid off his arm, but it clung tenaciously. Tears welled at the corner of his eyes, and he grimaced with pain. "The damned thing is biting me." Rivulets of blood could be seen beginning to trail down his arm. Groaning, Khalid swung his arm, cracking the shell against the rock wall beside him-to no avail.

Ben pulled a knife from his belt. "Hold still!"

Khalid froze, then a spasm of agony contorted his face. "Just get the thing off," he said between clenched teeth.

Ben slipped the blade between tentacle and skin. It was a tight fit. The creature's appendages clamped tightly to the flesh of Khalid's arm. Ben sawed through the meat of one tentacle, and greenish black ooze spurted from the amputated end. The thing tightened its other appendages, eliciting a groan from Khalid.

The monster's strength was fierce. If it constricts much more, Ben thought, it'll crush bone. He cautiously worked the knife under a second tentacle and cut. This time the thing twitched and loosened. After slicing through two more appendages, the creature released Khalid's arm, dropped to the cave floor, wobbled, and sucked its remaining tentacles back into its shell.

Khalid dropped to his knees with a low moan, a hand clasped over the wound, blood seeping between his fingers.

Ben kept an eye on the shell, black ooze dripping from its opening. With a scowl, he swung a boot and kicked the shell in a high arc over the pond. With a splash, the creature sank from view.

Ashley yelled at him, "Why the hell did you do that? We could have studied it. My god, it's an extinct species."

Ben pointed to Khalid's bloody arm. "Extinct, my ass."

"He'll live," Major Villanueva said.

Ashley watched him apply the bandage to Khalid's arm with a piece of waterproof tape. The SEAL, with his advanced training as a field medic, had taken over as soon as they had arrived back at camp. After cleaning the wound, he treated Khalid with topical and systemic antibiotics.

"Can he continue on with us?" she asked.

Villanueva shrugged one shoulder. "Nothing more than a deep puncture to the muscle of the forearm and some bruising. He'll be fine."

She nodded and turned away. Good. She'd hate to lose a team member before they had reached uncharted territory. As she passed the campstove, Halloway offered her a bowl of lukewarm chili and beans in a tin pan. She accepted it with a curt word of thanks and settled onto her air mattress with the pan balanced in her lap.

Ben had already scraped his bowl clean and looked greedily toward her plate. "So how's Khalid's arm?" he asked.