Atlantis

“Ready to activate pump,” said Ben.

Costas flicked the switch and the hum of the transformer was drowned out by the whine of an electric motor. Seconds later they could hear the spray of water being ejected into the darkness below.

“We’re simultaneously injecting air at atmospheric pressure,” Costas said. “The membrane’s strong enough to prevent the chamber from imploding under the weight of the seawater.”

The spray abruptly ceased and Andy gestured towards the screen. “We’re dry,” he announced. “Initiating phase four.”

Jack leaned down and peered intently at the holographic box for any changes in the appearance of the cliff face. The pulsating image showed the scanner had reactivated and was relaying data to the holographic converter.

“The rock-cut door seems to be holding,” he said.

Costas glanced at the hologram. “The probe is detecting fine leakage along the jamb. It’s exactly as we predicted.”

“We modelled this scenario last night on Seaquest,” Jack explained. “We assumed the stairs would lead to some kind of doorway. We also assumed that seawater would have worked its way through and flooded whatever lies beyond. The fact that the door didn’t spring open under the weight of the water inside shows there’s a rock-cut jamb that prevents it from opening outwards. There’s very little marine growth as the hydrogen sulphide in the water eats away any calcite secretions.”

There was a sudden sound of spray beneath them as the vacuum pump automatically kicked in to expel the puddle of water that had begun to accumulate at the far end of the chamber.

“There must also be some kind of locking device,” Jack murmured. “If this really is the way to the heart of Atlantis then they must have gone to great lengths to keep out unwanted visitors.”

“Either way, we’re going in wet,” Costas replied.

Katya looked bewildered. “ ‘Going in wet’?”

“Our only way of getting beyond those doors,” Costas explained. “We’ll walk out dry but then we’ll need to seal the hull and flood the chamber. If the doors hinge inwards we’ll need to equalize the pressure against the weight of water on the other side. Once inside we’re going to be underwater until we reach sea level.”

Ben and Andy were making final adjustments to a robotic arm which they had extended from the central unit to a point just above the chalked circle. After they double-checked its position Ben slid a locking pin through while Andy sat behind the console and tapped in a sequence of commands.

Costas leaned over to inspect the device before addressing the other two.

“That arm’s an extension of the laser we used to bore the hole in the casing. It pivots clockwise on a central axis and should slice through the hull with ease. Fortunately the Akula-class was made of steel, not titanium.”

“How will the hatch keep from imploding inwards when the chamber fills with water?” Katya asked.

“The cut’s angled outwards so the hatch will only open into the chamber and will reseat with water pressure once we’re gone.”

Andy swivelled round to face Costas. “All systems go. Ready to activate final phase.”

Costas gripped the edge of the walkway and surveyed the equipment one last time.

“Engage.”

Katya watched in fascination as the laser began to describe a clockwise arc on the submarine’s casing, the manipulator arm pivoting round the central unit like an outsized draughtsman’s compass. The cut was only a few millimetres wide and followed the line of the circle chalked by Costas round the GPS fix. After the beam had traversed the first quadrant, Ben positioned a small metallic tube against the cut. With a deft movement he cracked a miniature CO₂ cylinder at the back which punched a magnetic strip through to the exterior, creating a hinge so the hatch would swing back against the membrane of the chamber wall.

“Fifteen minutes to go,” Costas said. “Time to kit up.”

Jack lent a hand as Costas hauled himself up onto the walkway.

“The moment the hatch is shut there’s no safety net. Our lives depend on our equipment and each other.”

Slowly, methodically, he double-checked the self-contained life support equipment they had donned in the DSRV. After calibrating the decompression computer on his left wrist he inspected the sealings on Katya’s E- suit.

“The Kevlar mesh has good resistance to rock and metal,” he said. “The rubber sealings divide the suit into a number of compartments, so a leak doesn’t mean you’ll get completely flooded. Even so we’re going to have to be careful. At almost one hundred metres we’re below the deepest thermocline and the temperature will only be a couple of degrees Celsius, as cold as the Atlantic.”

After getting Jack to cast an eye over his equipment Costas disengaged a small console from his left shoulder. It had a digital LCD display and was connected to the manifold on his backpack.

“When that chamber floods we’ll be subject to the pressure of the surrounding seawater, almost ten atmospheres,” he explained. “That happens to be the same depth as the Minoan wreck, so we’re using our tried and tested trimix formula. Any deeper will stretch the envelope for oxygen toxicity. We badly need that passageway to go up and not down.”

“What about decompression sickness?” Katya asked.

“Shouldn’t be a problem.” Costas snapped the console back on its retainer. “At this depth the trimix is mainly helium and oxygen. The nitrogen increases as we ascend, the regulator automatically adjusting the mixture as the pressure decreases. Unless we linger too long we should only need a few brief decompression stops to let the excess gas dissipate from our bloodstreams as we go up.”

“We’ll be going up,” Jack asserted. “My guess is this will lead to some kind of peak sanctuary.”

“That makes sense geologically,” Costas said. “It would have been a Herculean task to bore horizontally through layers of compacted basalt. They would have run into vents and even the magma chimney. It would have been easier to tunnel upwards along the line of the lava flow, at about the angle of the stairway.”

“Well, we already know these people were brilliant engineers.” Katya spoke as she fine-tuned her two-way VHF receiver to the same frequency as the other two. “They could quarry an area the size of a football pitch, build pyramids more impressive than anything in ancient Egypt. I don’t think tunnelling would have posed any great obstacle for them.” She reinstalled the communications console on her helmet. “We should expect the unexpected.”

The only noise was the low hum of the generator as the laser worked past the halfway point. Unlike the ragged cut of an oxyacetylene torch the edge was as smooth as if it had been tooled by high-precision machinery. The steady advance of the manipulator arm seemed to count down the final minutes before they would step into the unknown.

Just as the laser was entering the final quadrant, there was a sudden vibration. It was as if an earth tremor had shaken the entire submarine. It was followed by a dull thump and a muffled clanging noise, then an ominous silence.

“Engage reserve battery!” Costas ordered.

“Already done. No break detected in the current.”

The electrical hum resumed as Andy yanked out the cord leading back to the DSRV and scanned the screen for faults.

“What the hell was that?” Jack demanded.

“It came through the hull casing,” Andy replied. “I can’t source it.”

“Not forward,” Ben asserted. “We’re only a few metres from the bow cowling and would know about any impact there. It must be aft, maybe just this side of the bulkhead sealing the reactor chamber.”

Costas looked grimly at Jack. “We have to assume the DSRV has been compromised.”

“What do you mean, compromised?” Katya demanded.

“I mean we’ve got visitors.”

Jack pulled back the slide on his Beretta and checked that a round had been chambered. After satisfying himself, he let the slide spring forward to close the receiver and gently flicked the catch to the safety position. He would be able to empty the fifteen 9 millimetre Parabellum rounds within seconds should the need arise.

“I don’t understand,” Katya said. “Is it our people?”