“Not the central passageway,” Jack said. “It’s too obvious.”
Katya was peering through the right-hand entrance and the other two gravitated towards her. They crowded together at the sill and nodded wordlessly to each other. Katya pulled herself forward and took the lead. The passageway was only wide enough for two of them side by side and barely high enough to hover upright.
It continued unswervingly for twenty metres, the smooth walls giving nothing away. The gap between Katya and the other two increased as Costas stopped to add another reel to the tape that trailed behind him while Jack waited for him. He put his gloved hand to the rent on his side.
He grimaced. “The water, it’s warmer. I can feel it.”
Neither Costas nor Katya had any sense of the outside temperature in their E-suits, and until now they had seen no reason to monitor the thermometers on their consoles.
“I’ve got a bad feeling about this,” Costas said. “There must be a volcanic vent that’s boiling it up. We need to get out of here.”
They suddenly realized Katya was not responding. As Jack anxiously swam forward, the reason became apparent. His earphones crackled with a crescendo of static that would have drowned out any reception.
“Localized electromagnetic field.” Costas’ voice became clearer as he swam alongside. “Some kind of lodestone in the rock, a concentrated mineral extrusion like the fool’s gold in the entrance chamber.”
A curve to the right showed where Katya had disappeared from view. They finned rapidly, their attention fully focused on the darkness ahead. As they rounded the bend the walls changed from a lustrous polish to the rough- hewn appearance of a quarry face. The view ahead blurred and wavered like a mirage.
“It’s scalding,” Jack gasped. “I can’t go any further.”
They had passed beyond the man-made walls and were now surrounded by the jagged contours of a volcanic fissure. Katya suddenly appeared through the murk like a phantasm in a desert storm and in that split second they sensed some dark force beyond, some denizen of the deep hurtling towards them with inexorable intent.
“Go!” Katya screamed. “Back to the passageway!”
Jack reached out towards her but was thrown back by an enormous surge he was powerless to resist. All they could do was try desperately to avoid the serrated edges of the lava as they tumbled through the water at terrifying speed. Before they knew it they were back within the smooth walls of the passageway. An immense tremor left them shocked and dazed almost ten metres in from the fissure.
Katya was hyperventilating and fighting to control her breathing. Jack swam over to her and checked her equipment. For a moment, a fleeting moment, he remembered his own fear, but he firmly parcelled it away in his mind, determined that it had burned its last and was now extinguished.
“I think that was the wrong way,” she panted.
Costas righted himself and swam back a few metres to splice the tape which had been severed by the force that had nearly annihilated them. They had re-entered the zone of magnetic disturbance and his voice crackled over the intercom.
“A phreatic explosion. Happens when water hits molten lava. Cooks off like gunpowder.” He paused to catch his breath, his sentences punctuated by deep pulls on his regulator. “And this fissure’s like a gun barrel. If it hadn’t blown through a vent somewhere behind us we’d be the latest addition to the sacrificial tally.”
They quickly returned to the three entranceways. They avoided the central one, continuing to trust Jack’s instinct. As they approached the left-hand entranceway, Jack sank to the floor, suddenly overcome by a wave of nausea as his body struggled to cope with the change from searing heat to the frigid waters of the passageway.
“I’m all right,” he gasped. “Just give me a moment.”
Costas looked at him with concern and then followed Katya to the sill of the doorway. She had still not recovered from the shock and her voice was tense.
“Your turn to lead,” she said. “I want to stay beside Jack.”
CHAPTER 19
The left-hand tunnel angled abruptly downwards, the walls constricting further and funnelling them into the bowels of the volcano. The image fuelled the turmoil in Jack’s system as he battled his wound. Now he also had to cope with the debilitating effects of increased pressure as they sank into the icy blackness of the tunnel.
“I can see steps chiselled out below,” Costas announced. “We’ll have to pray it levels out soon. Another ten metres and we’re gone.”
Costas anxiously monitored his depth gauge as they descended, their automatic buoyancy compensators bleeding enough air into their suits to keep them from plummeting. After a few metres the drop increased alarmingly. For a moment Jack and Katya could see nothing, their vision obscured by the cloud of bubbles from Costas’ exhaust as he sank directly beneath them.
“It’s all right,” his voice came up. “I can see a floor.”
The steps below turned to footholds as the face became vertical. Jack sank down the final few metres and landed on his knees. Katya followed.
“One hundred and sixteen metres,” Costas muttered. “That’s it for this trimix solution. Another few metres and the regulators would have aborted.”
There was no response from the other two and Costas anxiously scanned their faces for signs of nitrogen narcosis. As his eyes grew accustomed to the surroundings he realized why they were silent. The claustrophobic confines of the tunnel had given way to a vast magma chamber, its fiery contents long since dissipated to leave an elongated cavity like the hall of a medieval castle. The analogy seemed particularly apt as Costas looked back at their point of entry. The tunnel above gaped like the chute of an ancient chimney, the rock face below spreading into a recess like a baronial fireplace.
The chamber seemed an entirely natural phenomenon, its nave-like shape the result of titanic forces in the earth’s crust rather than any human agency. As Costas’ mind adjusted to the size of the room he began to see swirling patterns in the basalt on either side, a tumult of twisted shapes as if a cascading river of lava had frozen in mid-flow. Suddenly he saw what had captivated the other two. It was as if he had been presented with a brain- teaser and his mind had intuitively focused on the forms of the geology. As soon as he recognized the alternative, a fantastic scene revealed itself before his eyes. The walls were covered with a spectacular menagerie of animals painted and incised into the rock, their forms respecting the contours of the chamber and taking advantage of natural patterns in the basalt. Some were life-sized, others larger than life, but all were rendered in a highly naturalistic style that made their identification easy.
At a glance Costas could make out rhinoceros, bison, deer, horses, huge cats and bulls. There were hundreds of them, some standing alone but most in overlapping groups, image after image piled on top of each other like a reused canvas. The effect was startlingly three-dimensional, and combined with the mildly hallucinogenic effect of the nitrogen, they seemed to Costas to be alive, a mass of slavering beasts surging towards him like some wayward mirage.
“Incredible.” Jack finally broke the silence, his voice hushed with awe. “The hall of the ancestors.”
Costas shook away the phantom image and looked questioningly at his friend.
“You hinted at it,” Jack explained. “That there were people here long before those first bull sacrifices. Well, here’s your evidence. These paintings are from the Upper Palaeolithic, the final period of the Old Stone Age when people hunted big game along the edge of the glaciers. We’ve just swum back thousands of years to the first explosion of human artistic creativity, thirty-five to twelve thousand years ago.”
“How can you be sure?”
“Look at the species.”
They finned in line abreast towards the centre of the gallery, the exhaust from their breathing rising in great shrouds of silver towards the ceiling. Everywhere they aimed their headlamps, new marvels of ancient art appeared. Despite the urgent need to press on, they were drawn by the enormity of what they were seeing.
“There are no domesticates,” Katya ventured. “No cows, sheep, pigs. And some of these look like extinct species to me.”
“Exactly,” Jack said, his excitement evident. “Ice Age megafauna, outsized mammals that died out at the end
