44

  January 24, 5:44 P.M. NZDT

  Eight miles under the Pacific Ocean

  “How much oxygen do we have left?” Adam asked.

  Bryan tapped a gauge. “After jettisoning our reserve tanks by the fissure, we have at best four or five hours. Same with the batteries.”

  Adam gritted his teeth.

  Just enough time to write our obituaries.

  Phoebe seemed unperturbed. She continued to study the life around her. She had a notebook in her lap and drew rough sketches. Over the past hour, she and Datuk had been whispering, speculating, theorizing about everything. He suspected—at least on Datuk’s part—that it was to distract from the inevitable.

  Phoebe pointed to a shining swirl of hundreds of polyps. They swept past and cascaded in a complicated, coordinated dance. “That behavior looks less like the schooling of fish and more like the murmuration of starlings.”

  Datuk leaned closer. “They must be using a combination of bioluminescent patterns and sonic calls to synchronize their movements. Such behavior could explain why the species appears to be more intelligent than the average octopus. With rare exceptions, octopuses live solitary lives. Intelligence is whetted far better in a societal structure, which requires honing communication skills and cooperation.”

  Adam tuned them out and sighed heavily. He turned the other way. He looked toward the dark forest and pictured the fissure back there. They had monitored it with their sonar and watched the lowermost edge close to a narrow gap. It looked like the fissure might be wider up higher, but there was no way to get through the squeeze at the bottom.

  Motion drew his gaze to the edge of the black forest. Flocks of the bioluminescent creatures swirled at the fringes, darting among the trunks, as if wanting to enter but still wary of the radiation. As he stared, more and more gathered at that edge, a frustrated army of them.

  “What are they doing?” Adam mumbled.

  Phoebe glanced back. “What’s wrong?”

  Adam swung to Bryan. “Can you spin us around?”

  The Aussie nodded and boosted the thrusters to turn the Cormorant. They all watched the gathering at that blackened fringe of forest.

  “It looks like something’s calling to them,” Datuk said. “But they don’t dare cross the irradiated area to get there.”

  Phoebe pulled up the acoustic headphones. As she listened, two deep lines creased her brow. She turned to Bryan and pointed at an earpiece. “Can you put this on speaker?”

  He flipped a switch, and a low roaring filled the sphere.

  A few passing polyps spun and circled back to the Cormorant. Luminous eyes peered inside, studying them.

  “They hear it, too,” Datuk said. “It’s clearly attracting them.”

  Phoebe nodded. “Someone’s broadcasting it. From above. It must be echoing through the gap in the trench.”

  “But what is it?” Adam asked. “Who’s sending it?”

  Bryan pointed at a monitor to the right of his helm. “It’s coming from the Titan X. It’s accompanied by a text message.” He glanced back. “From our old shipmate Monk.”

  Adam leaned over, nearly crawling atop Bryan.

  The Aussie elbowed him back. “I’ll send it to all your screens.”

  Adam returned to his seat and read a long missive from Monk. It told a story that went back two centuries. He was clearly trying to share as much intelligence as possible.

  “Bullroarers?” Datuk said. “That’s what we’re hearing? That’s what’s agitating these creatures?”

  Phoebe looked unsurprised. “The species communicate via harmonics. Maybe it’s due to the silicon in their DNA or some amplification through the crystalline structure of their coral skeletons. No matter the reason, it’s clearly a powerful tool for them.”

  Adam turned as the roaring dimmed in the sphere. The sonic communication slowly faded. He pictured the Titan X sailing away from these waters, heading for Raoul Island.

  They’ve moved out of range.

  Frustrated, Adam turned to the others. “Does any of this help us with our situation? Monk clearly has no idea if we’re trapped or not. He must have dispatched as much as he could, letting us know where to look for him if we ever made it out of here.”

  Phoebe ignored his question and played with the sonar array, casting out pings. She leaned over Bryan and checked their positional reading and compass.

  “What are you doing?” Adam asked.

  Phoebe turned to him. “I know how to get out of here.”

  “What?” Datuk frowned at her. “How?”

  She pointed to the sonar screen, which showed a forward-looking scan of the far wall. The sounding showed a patchwork of solid rock and black spaces that failed to return a ping.

  She pointed to the largest. “That’s got to be a tunnel. It’s heading in the direction of the coordinates that Monk sent us for Raoul Island.”

  “You think it’ll lead us there?” Bryan asked.

  “Maybe. That account spoke of the Aboriginal myth of the Rainbow Serpent, how it could travel around the globe via a secret watery world.” She waved to encompass this cavernous space. “From waterhole to waterhole, from one thin spot to another.”

  “And Raoul Island is its legendary home,” Adam said.

  “Then—like Rome—all roads must lead there.”

  “But how can we be sure we pick the right path?” Datuk asked. “It could be a maze once we leave this cavern.”

  Phoebe shrugged. “We either try—”

  “Or we die,” Adam said, finishing her thought.

  6:17 P.M.

  With a walkie-talkie in hand, Monk crossed the stern hold of the Titan X. Its rear door lay open to the sea. Ahead, the western side of Raoul Island filled the view. The yacht had dropped anchor a mile off the coast. Two spits of land reached toward them, framing a wide bay.

  Directly ahead, a tall volcano seethed and boomed. Lava bombs blew in huge fiery arcs from its flaming caldera. They slammed into the bay with sizzling blasts or crashed into the gutted forests. The island had once been a lush atoll covered by dense jungle and dotted by tiny lakes. It was now a flaming coal in a dark sea. Blackened trunks prickled its slopes. Solitary torches burned in the smoke-shrouded gloom.

  To the south, volcanos marched off into the distance, heading toward the coast of New Zealand. The closest was as fiery as Raoul, but the others faded with distance into smoldering glows.

  Monk stepped out onto the apron of decking.

  Kowalski waited to one side. “Don’t want to go swimming out there,” he warned, knocking red embers from his cigar into the sea, adding to the thick layer of ash. Several patches of the sea flickered with flames.

  But it wasn’t the pall or fires that concerned the big man.

  Across the bay, hundreds of spiky balls spun through the ash. Gray had warned them about those fiery mines and the dangers they posed.

  Monk raised his walkie and radioed the bridge. “Kokkalis here. I’m in position. Do you copy?”

  Byrd responded. “All set at our end. On your word, we’ll pipe that recording through the ship’s sirens and emergency speakers. It’s going to get loud. You sure you want to be out in the open?”

  “Light the cannon,” Monk said and lowered the walkie.

  He intended to be on hand to witness any change.

  Kowalski was down here on a smoke break.

  A moment later, a low roaring rose around the ship, echoing over the sea. It quickly rose in volume. Monk winced at the noise. Kowalski clamped his large hands over his ears.

  It grew into a resounding alarm. The noise reverberated throughout the ship. It vibrated the decking underfoot and shivered the layers of ash in the water.

  The Titan X had become the world’s largest tuning fork.

  The noise shook through Monk’s frame, prickling his skin.

  He took a step deeper into the hold, trying to escape the onslaught.

  Some frequency in that roaring spasmed his prosthetic. The EW module burned under his palm, hot enough he thought it might melt through his skin. His head throbbed. The pain lanced across his scalp, rising from the scar behind his ear that marked where his cortical implant had been placed.

  Monk remembered how Gray had mentioned that the ELF signal had knocked out the electronics in a lunar lander and maybe the Chinese nuclear submarine.

  Does this roaring contain some wavelength just as damaging?

  He stumbled backward, his sight blurring.

  Shouldn’t have come outside.

  Then Kowalski was there. He grabbed Monk and held him upright. Kowalski pointed past the stern.

  Monk blinked and squinted. Raoul Island still smoldered and smoked. Its caldera remained fiery. But the cascade of flames had died away. The flows of lava down its flanks appeared to be petering out. The mountain gave one last burp of fire, then stayed quiet.

  Monk shifted forward, still beaten down by the roaring. He searched to the south. The line of volcanos had similarly subsided. The distant glows had vanished. The nearest peak slowly disappeared into the gloom.

  He raised his walkie and yelled into it. “Byrd, cut it off!”

  He was deaf to any acknowledgment, but the sirens and speakers wound down, finally dying away.

  With his ears still ringing, he turned to Kowalski. “I didn’t think it would work,” he admitted. “Especially that fast.”

  “What are you talking about?” Kowalski scowled at him. He lifted his cigar, which had burned down to a stub. “It’s been nearly an hour.”

  “What?”

  Kowalski dug a knuckle into an ear. “Don’t know if I’ll ever hear right again.”

  Monk stared at his prosthesis and rubbed the side of his head. Time had slipped for him. He opened and closed his fist. All seemed fine now.

  “Look!” Kowalski pointed across the bay.

  Without the torch of the volcano, the world had grown darker. Across the water, the layers of ash glowed, suffused with soft lights from below. The patches grew steadily brighter, skimming and gliding. More and more rose, until the bay was swarming with them. A few broke through the powder, shining in brilliant flickers of emerald and cobalt.

  The Rainbow Serpents.

  Monk stepped out onto the deck, awed and breathless. Still, he felt wobbly and caught a hand on the steel A-frame that hung over the stern. It was the launch-and-recovery system for the Cormorant.

  Reminded of the others, he raised his walkie to his lips. “Bridge, any word from the Cormorant?”

  He waited for a response. It was slow coming, dragged by the grim news.

  “No,” Byrd said. “We may have to consider them lost.”

  6:45 P.M.

  “Do we have any clue where we are?” Adam asked.

  Phoebe heard the desperation in his voice and understood it. They had been traversing this labyrinth for more than an hour. They would soon be running out of oxygen.

  She shook her head and studied the sonar. The Cormorant hovered in a large cavern. It was full of coral, flowing with vibrant, radiant life.

  By now, even her enthusiasm had dimmed for this lost landscape.

  “Four tunnels and chasms extent eastward,” Phoebe reported. “I can’t tell which one might lead to Raoul Island.”

  “If any of them do,” Datuk added, exhausted and defeated.

  Bryan offered the only option open to them. “We can always flip a coin.”

  Phoebe frowned, unwilling to accept defeat.

  After leaving the first cavern, they had discovered a maze of crisscrossing tunnels, jagged rifts, and bottomless chasms. Even their compass betrayed them, at times spinning wildly in some magnetic flux. She was not sure she could even trace their way back to where they started.

  The only hopeful sign came from their external pressure reading. It had been steadily dropping. Bryan had to keep blowing ballast to adjust their buoyancy. It indicated that they must be edging upward. The external pressure was currently at 15,000 psi, which would place them at a depth of around ten thousand meters.

  “We have to be close,” Phoebe said. “The island was only eight miles from the Titan X’s position. And by the time we exited the first huge cavern, we had already crossed two miles off that distance. We must be nearing the island’s waters by now.”

  “Even if that was true,” Adam said, “how do we get up there? The sonar’s not picked up a single gap, crack, or seam in the roof over our heads. Just endless rock.”

  Phoebe sighed and pointed. “Then we keep going. We have no choice.”

  Bryan engaged the thrusters and set them gliding forward. Their motion drew the attention of a few passing polyps. They spun closer, casting an inquiring eye inside at the sphere, then sped off with a whip of their bodies.

  More followed and cascaded around them, flashing and streaming with lights. She read some urgency in their pattern, but it was likely only a reflection of her own tension.

  “Must be rush hour,” Bryan mumbled.

  Phoebe grinned—then noted that he was right. She ignored the sonar and studied the growing river running alongside them. She might have dismissed it, except the polyps were all blinking the same urgent pattern as the first couple.

  Bryan started to drift the Cormorant away, to get out of the traffic flow.

  Phoebe reached over and pushed the yoke back. “Follow them!”

  Adam leaned forward. “What is it?”

  She ignored him and donned the acoustic headphones. The chorus of the coral forest filled her head. She squinted, trying to pick up a deeper tone, but it was too noisy.

  Ahead, a branch of nesting polyps shot high and dove into the flow.

  Adam touched her shoulder. “Phoebe?”

  She pulled off the headphones and turned to him. “The way the polyps are flashing, the army that’s building. It’s like back at the first cavern, when they bunched at the fringe of the irradiated forest.”

  Datuk understood. “They’re responding the same way. Likely to the same signal.”

  “The roaring that Monk transmitted to us,” Adam said.

  “He was planning on broadcasting that same signal over the waters of Raoul Island.” Phoebe searched ahead. “I think the creatures are hearing it now, heeding that siren’s call like before.”

  Adam sat straighter. “Then they could lead us out of here.”

  “I’m not waiting.” Bryan tilted the Cormorant and maxed their thrusters. “Don’t wanna get left behind.”

  They followed that shining river, chased by rainbows in their wake. The flock swept into a far tunnel, across a smaller cavern, and up a long spiraling rift.

  Bryan blew ballast to keep up.

  Phoebe flashed their lights, roughly in synch with the polyps, trying to signal her intention: We’re coming, too.

  They reached the end of the spiral and exited into a bowl-shaped cavern. It was full of giant coral, but its nests were mostly empty. Only a few handfuls of polyps spun and drifted through this dark forest.

  Adam lunged forward and tapped at the sonar screen. It showed a map of the roof above. “A seam! Right there!”

  Bryan eyed the dark shadow and sat straighter. “Emptying all ballast.”

  The Cormorant sailed upward. The vehicle spun as it ascended. A luminous tide of polyps rode along with them. They raced together toward that crack in the roof.

  Phoebe watched the polyps. She knew these creatures could travel much faster.

  “They’re staying with us,” she realized. “They don’t want us to fall behind.”

  Adam pointed. “We’re approaching the seam. Looks like it’ll be a snug fit.”

  “I’ll get us through,” Bryan promised.

  But the choice was taken from them.

  Something bumped them from below. Their ascent quickened. Phoebe leaned between her legs and stared under her. A huge polyp flared and whipped its tentacles below the Cormorant. It was the size of an elephant. It propelled them upward.

  “We’re going too fast,” Bryan warned. “At this speed, our thrusters won’t be able to finesse any course corrections or adjustments.”

  “Then let’s hope that beast under us has good aim.” Adam looked up. “Because there’s no turning back now.”

  Their pace steadily increased.

  “Hold tight!” Adam called.

  Lit by the shining river above, the rift swept down toward them. Then they were in it. Phoebe sucked in her breath, trying to squeeze herself tighter. The walls swept mere inches to either side.

  The passing cliffs were festooned in swaths of waving anemone and thick mats of algae. From all the growth, this rift had to be old.

  She understood what they must be traveling through.

  One of the Aboriginal thin spots.

  She imagined there must be a similar one in the seas near Mount Tambora, an ancient window between their two worlds.

  A few minutes later, the Cormorant shot out of the rift and into open water. Their caretaker gave them another hard push, then swept away. The luminous tide flowed in a glowing river through the black water, heading for Raoul Island.

  “Looks like we’re on our own,” Adam said.

  “No worries, mates.” Bryan pointed a finger up. “I know the way from here.”

  Phoebe checked their depth. “Five thousand meters.”

  “With the momentum we’ve got,” Bryan said, “we should be topside in twenty minutes.”

  He was wrong.

  It took only fifteen.

  The Cormorant reached the surface and popped high, nearly clearing the water. The vehicle bobbed back down, then up again, until it finally floated atop the waves.

  Bryan clambered over them to pop their hatch.

  Adam dropped into the pilot’s seat, leaning shoulder to shoulder with Phoebe.

  They stared across the waves to the smoldering remains of Raoul Island. The bright lights of the Titan X glowed a mile off, anchored near the mouth of a bay. The waters there stirred and glowed in the hues of a rainbow.

  “Did we do it?” Phoebe asked.

  Adam touched her chin and turned her gaze farther west.

  The black pall of clouds had dissipated enough to show a peak at the horizon, at the curve of a world that looked new to her eyes.

  But one detail remained eternal and full of promise.