strap with one hand and releasing the carabiner with the other, then injecting air into both of their buoyancy compensators. He watched the line snake away and disappear into the molten mass below them, and turned Costas round to face him. ‘You okay?’
Costas was wide-eyed, his visor fogged up around the edges from his exhalation. Jack had a sudden sickening feeling. They had just lost their one lifeline, and they had expended more air than they had bargained for. Costas returned his stare. ‘I think that’s twice very lucky,’ he said hoarsely. ‘Let’s get up there, do what we have to do and get the hell out of here.’
As they swam upwards, Jack turned to look out over the lava lake. A surge was rising in the middle, then moving along as if something were swimming just beneath the surface like some ancient spirit monster. Suddenly the mass rose in a giant bulbous dome and split open, disgorging a huge bubble of gas into the water. A second later there was a blinding flash and Jack could see the pressure waves in the water surging towards them. Costas clung to him, pressing his visor against his. ‘Brace yourself!’ The shock wave pushed them violently towards the rock face, and then they were pulled back again over the lava lake by the implosion. Jack held on to Costas with one hand and finned with all his strength back towards the rock-cut door. He seemed to be getting nowhere, as if this were a bad dream, the door impossibly beyond his reach. Then the sucking force of the implosion miraculously relented, and they came to the ledge below the door.
‘What the hell was that?’ Jack said, panting.
‘Phreatic explosion.’ Costas’ visor fogged up as he struggled to regain breath. ‘It happens on land when lava flows over pockets of water, superheating it. Somehow that big bubble of gas under the surface of the lava must have had the same effect, sucking in water, encasing it and boiling it up.’
Jack stared up at the carved lintel above the doorway in front of them. Costas followed his gaze, panting, then he saw what Jack had seen. ‘Symbols. Ancient writing. Is this what you saw before?’
‘It’s fantastic.’ Above the doorway was the rectilinear Atlantis symbol, with other symbols on either side, familiar from the syllabry they had discovered five years before but not yet translated. They looked freshly carved, as if done just before the flood, and several looked only partly completed. Beneath them Jack could make out other symbols, very eroded and clearly much older, some of them looking as if they had been partly chiselled away. He activated his camera. There was no time for detailed recording now. He was jittery with adrenalin, and checked his computer readout. Fifteen minutes of breathing gas left at this depth. He was conscious that the danger had made the reflective part of his mind shut off in the focus on survival, on dealing with each new threat as they encountered it, and that he needed to maintain an awareness of the bigger picture, of just how close they had come to never leaving this cavern alive. He stared at the entrance. He would need five minutes, just to look. With the lava rising inexorably, it was the last chance before whatever lay inside there was lost forever.
‘Jack, you’ve got a problem.’
‘What is it?’
‘Check your internal temperature readout.’
Jack looked sideways inside his helmet, scanning the digital readout. ‘Twenty-six degrees Celsius. I thought it was getting a little warm. I’ll adjust the thermostat.’
‘Don’t do that yet. Wait till you really need it. You’ll blow the system.’
‘What do you mean?’
‘It must have been the heat when we were close to the lava. You’ve got a leak from your coolant reservoir, Jack. You can’t afford to be that close to extreme heat any more, as you’ll soon have no way of cooling down.’
Jack shut his eyes, trying to control his breathing. For a moment he felt nauseous, a flutter in his stomach, the sickening feeling of the walls closing in. Part of him wanted to swim up and dump his air against the ceiling, to create a pocket where he could rip off his helmet and be free, but he knew that to do so would only be a brief illusion of normality in an air space that would feel far more confined than the water below. He swallowed hard. Keep focused. He sucked on his water tube, then looked into the doorway and tried to ignore the lava, which was rising up the rock face below at an alarming rate. Costas had already unzipped his front pocket and disgorged the ROV, which he was testing like a remote-controlled helicopter. Jack realized where the nickname Little Joey had come from. It looked like a miniature robotic kangaroo, with hind legs, a swivelling video aperture for a head and a tethering cable for a tail, leading to a spool on Costas’ chest. The robot craned its neck around and peered at Jack with its single video eye, and then jetted back to Costas, hovering in the water in front of him. Jack swam ahead to the door entrance, then switched on his helmet lights. ‘I’m going in. Five minutes, no more.’
Costas put a hand on the ROV’s neck. ‘Little Joey will be following you. He can send back remote signals, but I’m keeping him on the tether in this place. If you see anything, hold him like I am and put him on to it. Remember, I’m seeing what he sees on the screen inside my visor. Just point and I’ll drive him forward. Then you come out, pronto.’
Jack stared at the ROV, its single camera eye encased in a sphere of glass. It angled its head around and looked at him, the black lens cap half-down like an eyelid. He realized that he was cocking his own head in the same way, as if they were querying each other. He shook his head in disbelief at what he had just done and looked away. The ROV was not alive. ‘Roger that.’
‘Remember what Macalister said. No disappearing down holes.’ Costas’ voice crackled. ‘That electromagnetic interference is increasing again. There must be a lot of ferrous material in the lava here. I may be out of contact with you.’
Jack surged forward, passing through the entrance and finning down the rock-cut tunnel. After about ten metres the tunnel became a T-junction. Jack stopped and checked his remaining time. Four and a half minutes. It had to be one or the other. The ROV came up alongside him and angled to the right, illuminating the passage. Costas’ voice crackled on the intercom. ‘Jack, give me a confirmation on what you see. I think I’m looking at another entranceway.’
‘That’s an affirmation. But there’s one on the opposite side too.’
‘Little Joey’s pointing the way. Left would take you to the surface of the volcano, now under tons of lava. Right would take you towards the location of that open-air platform we saw five years ago, a more likely place for some kind of sanctuary.’
Jack heard crackling as Costas tried to say more, and then a low hum. Whatever it was that was causing the interference, this place was the epicentre. He had no time to weigh up the options. He swerved right and followed the ROV into the passageway, kicking hard to get beyond it. He swam about ten metres further, then followed the passageway as it veered left. Ahead of him the tunnel was partly blocked with rough-hewn squared stones that looked as if they had been hastily assembled. Whatever it was that had been beyond there on the eve of the flood seven thousand years ago, somebody had wanted it cut off. An aperture still remained, big enough for someone unencumbered to crawl through, but not big enough for a diver with gear. Jack rolled sideways to fit the hole and shoved his head through, his headlamp angled upwards. It was a chamber, maybe eight metres across. He could see jagged protrusions of lava from the eruption five years ago, visible beyond another wall of crude masonry that blocked what must have been the open front of the chamber, clearly a cave in the face of the volcano. He twisted to the left, lying on his back, and saw that the opposite side was natural rock, a wide opening that extended inwards. Big multifaceted crystals of quartz were visible in the wall just to his right. He flicked on his helmet video camera, moving his head from side to side to ensure maximum coverage, then struggled to twist around until he was lying on his front. He strained to raise his head up, angling the lamp as high as he could, then he froze with horror.
He was staring at a human face. It was a skull, embedded in the floor of the chamber. The bone had been plastered over and was partly covered with a rough calcite accretion that must have formed underwater after the flood. One eye socket was open, and the other was filled with plaster and a cowrie shell, as if the skull were staring at him through the slit. Jack instinctively recoiled, his breathing coming in short rasps, and then he forced himself to raise his head higher and look beyond. It wasn’t just one skull. There were dozens of them, all embedded in the floor and facing him, all of them plastered over in the same fashion. The accretion as well as the anoxic conditions of the water must have preserved them. Then he saw another skull lying on its side, unplastered, with the jawbone hanging away, and shapes on the floor covered with accretion. Beside the skull nearest to him was a stone basin about half a metre high on a plinth. He reached out his left arm and put his hand inside, scraping the interior, then pulled his hand away and stared at his glove. It was smeared in a thick, viscous substance that seemed to have lined the bottom of the bowl, some kind of residue. He brought his hand under his headlamp beam and stared at it, his heart pounding. The substance was a deep maroon colour.
He was not only looking at the people of Atlantis. He was touching their blood.
