They turned and were swimming toward the doorway when a low rumble trembled through the structure. Several large blocks dislodged in the chamber above them and dropped in a cloud of debris, barring their exit as the small earthquake shifted the foundation. Sam and Remi held deathly still until the shock subsided, their light beams filtering through the cloud of sediment. They exchanged a glance through their masks—their means of escape was sealed off.

Sam swept the area with his flashlight, looking for another opening. At the far end of the chamber, the light disappeared into darkness where previously there had been wall. Sam pointed to the new gap and swam cautiously toward it, Remi by his side. They reached the opening and found themselves peering into a passageway encrusted with marine life, long tendrils of seaweed drifting in the water like wisps of green smoke. Sam looked over at Remi and gestured at his air supply gauge. Remi glanced at hers and gave him a So-so signal with her right hand.

They swam into the narrow corridor together, Sam in the lead, the glow of his lamp of little help through the curtain of marine growth in their path. He groped with his free hand as the passageway curved, and slowed when he came to a bend, the bottom rising in a mound of debris.

Another glance at his watch confirmed that they were almost out of time—their ascent would require a decompression stop to allow the nitrogen in their systems to disperse, which would require air to breathe. At the rate they were going, they’d run out before they had sufficient decompression time and would have to rush to the surface, risking the painful and sometimes fatal condition known as the bends.

Which assumed they’d be able to escape in the first place and didn’t drown when their dwindling air supply ran dry.

Sam pushed ahead until he came to a point where the rubble pile rose so high it blocked his way forward. He looked overhead at the ceiling and spotted a narrow section of opening created by several of the stone blocks collapsing. He inched to it and groped along the rim. More sediment filled the water as he broke loose a crumbling edge.

After two minutes of painstaking effort, he’d cleared an opening large enough to squeeze through without his tank. He slipped out of his BCD, took a final deep pull of air from his regulator, and then swam up into the darkness, pulling his rig along behind him. Remi waited, and twenty seconds later Sam reappeared and gestured for her to follow him up.

She repeated his maneuver with her BCD and wriggled into the gap. Once through the breach, they were in another chamber, this one smaller than the expansive one they’d entered through. Their lights scanned along the walls, and Sam pointed to where the sea growth was waving.

Remi swam toward the corner, slid her dive knife from its thigh sheaf, and hacked away at the seaweed until she’d cleared a section. Shattered blocks littered the floor beneath, and they could both make out another opening in the ghostly glow of their lamps, this one larger than the previous one. Remi took the lead and just managed to make it without having to remove her tank. Sam wasn’t so fortunate and had to remove his harness again before slipping through.

They now found themselves enveloped in a solid mass of seaweed. Sam and Remi cut through it with their knives. His blade encountered stone, and Sam pushed himself upward, continuing to cut.

A shaft of light pierced the gloom when his knife sliced through the last of the seaweed. The glow increased, and then they were in open water, on the far side of the ruin from where they’d entered. Sam drove through the water to where Warren was waiting at the entry and motioned to him to return to the surface with them. The Australian gave him an acknowledgment, and then Sam and Remi were rising, the sun’s rays seeping through the water above like a starburst.

Warren shared his air at the decompression stop, but still the tanks were empty by the time they reached the surface. Sam gasped in relief as his head popped out of the water, Remi close behind him, and they bobbed in the gentle waves, catching their breath, the Darwin’s distinctive crimson hull fifty yards away.

Ten minutes later, they had shrugged off their dive gear, dried off, and changed into shorts and T-shirts. After a brief discussion about how to best proceed, Sam and Remi returned to the pilothouse with Sam’s dive bag in tow, where Leonid was seated by the monitors, his expression typically dour.

Sam sat next to him and told him about the earthquake and near miss.

“You’re lucky you made it out alive.”

“That seems to be how our fortunes run, thank goodness.” Sam paused. “Your theory that there have been a decent number of earthquakes slowly eroding the ruins seems accurate. That wasn’t a very big one, but it was large enough to cause damage and almost trap us.”

“Why did you tell the others to come back up?” Leonid asked. “They were outside and barely felt anything.”

“Because we need to discuss what we saw inside the big structure and I don’t want to repeat myself,” Sam said.

Warren had joined Des by the helm. The rest of the dive team stood around the area, waiting to hear what Sam and Remi would say. Sam cleared his throat, and his gaze slowly swept the room before settling back on Leonid.

“Remi found something that changes everything.”

“What?”

Remi interrupted. “First, let’s talk about what we didn’t find. There was no treasure.”

Leonid’s shoulders sagged almost imperceptibly. Remi smiled and continued. “That would have been nice. But one of the things we saw were deep grooves in the walls of a chamber beneath a larger room that appeared to be a central gathering place. It’s hard to know until we clean everything off, but I’d say that the building was the main temple and the chamber was a treasure vault.”

“Grooves in the walls?” Des asked, his tone puzzled.

Sam nodded. “Yes. Carved into the stone. Once we get the hoses in there and clean the area, my hunch is we’ll find glyphs covering every surface in the chamber. Probably depicting holy places, or maybe images of gods.”

“How can you be so sure?” Leonid asked.

Remi raised an eyebrow. “Because the carvings were filled with gold.”

“Gold!” Warren blurted.

Leonid appeared puzzled. “But I thought you said there was no treasure.”

It was Remi’s turn to nod. “That’s right. There were only traces of gold left in the carvings. The rest had been removed. I could see where they’d dug it out of the etchings. But they couldn’t get it all.”

“They? Someone has been inside this temple before us?” Leonid asked.

“That’s right. There’s evidence on every wall. Probably a team of divers in surface-breathing equipment. You can make out where the hoses scraped the edges of the openings, rubbing at them. They weren’t taking any care to conceal their presence, that’s for sure,” Remi said.

“But surely we’d have heard about a find of this magnitude. Are you saying that someone located a modern-day Atlantis and didn’t tell anyone?”

“Obviously, that’s puzzling. Since we never heard of it, as unlikely as it sounds, that appears to be the case.” Remi paused. “It had to be a painstaking process to chip all the gold out of the walls—it probably took weeks of work with a team of divers.”

Leonid shook his head. “I don’t understand. Who beat us to this?”

Sam eyed him. “We can’t be certain . . . but Remi found a clue.”

“A clue?” Warren asked.

“That’s right.” Sam reached into his bag, extracted the object he’d brought from the chamber bottom, and considered it for a long moment before holding it up. The men drew nearer, pressing close to see what Sam held. Leonid was the first to react with a snort.

“What is that? A piece of junk?”

“Not junk, Leonid.”