“Is there anything else above the surface?” Nina asked.

The 3-D image jolted disconcertingly; the Atragon hadn’t changed course, but the laser scanners had been redirected to look off to one side. “I can see a few bumps where there might be things under the surface, but nothing actually standing out. How tall is this thing?”

“If it’s the size we think it is, it should be about sixty feet tall. Eighteen meters.”

“If that’s the case, then it’s maybe half exposed. There’s a lot of silt piled up around it.” The image shifted back to the temple.

“Sharkdozer, move in closer,” Kari ordered. “Head to the north end, keep clear of the Atragon.”

“Gotcha,” said Trulli. The second 3-D display showed his advance.

“Jim?” Nina asked. “Can you circle the building, please? I want to see what it looks like from the other side.”

Baillard complied. The maneuver took a couple of minutes, revealing a view much the same as their first sight of the temple. Its curved back, partly buried by sediment, reminded Nina of a turtle’s shell.

“Hey, Evenor,” said Trulli excitedly, “the north end here, the sediment’s lower. It must have been cleared away by the current. I can see more of the wall.”

Nina quickly switched her attention to the Sharkdozer’s screen. There was a smooth, almost bowl-like depression at the northern end of the temple, as though someone had used a giant scoop to clear the silt away. “Can you get in closer?”

“No worries. Hold on a tick.”

It took rather longer than the promised tick, but a few minutes later Trulli brought the hefty submersible to a hover a short distance from the temple wall. “I’m going to take a sonar reading,” he announced. “Hang on.”

One of the monitors flashed up a jagged graph. Nina couldn’t make head nor tail of it, but to the submersible pilot it was as clear as a photograph. “There’s something under the sediment-or rather, there’s something not under the sediment. Could be a hole in the wall.”

“Room to get Mighty Jack through?” asked Baillard.

“Maybe. Evenor, do I have permission to clear the sediment?”

Kari looked at Nina, who nodded in excitement. There was a way into the temple! “Go ahead, Sharkdozer.”

The operation that followed was frustratingly slow. Nina forced herself not to rap her nails on the desktop as Trulli moved his sub away from the temple. He carefully lowered the pump module to the surface about a hundred meters off to the northeast, extending its “tail” in the direction of the current, then returned to the temple. The Atragon’s LIDAR display showed the connecting tube stretching between the pump module and its mother ship as the Sharkdozer returned to position, taking up station above the base of the northern wall. The whole process took over twenty minutes.

“Ready to go, Evenor,” Trulli said at last. “Just give the word.”

“Go for it!” Nina cried, to everyone’s amusement.

The pump started.

Like the world’s largest vacuum cleaner, the Sharkdozer began to suck the accumulated silt into its gaping maw. The pressure difference created by the pump wasn’t huge, but it was more than enough to draw the layers of sediment into the pipe and through the detached module to spew out of the waste pipe one hundred meters away. The prevailing current gently swept the expanding cloud of suspended particles away from the temple. The value of a technique that had initially struck Nina as overcomplicated now became clear; simply digging up the silt would have wiped out visibility within seconds.

Another ten minutes passed with agonizing slowness, the Atragon providing a ringside view as the Sharkdozer slid from side to side over the foot of the wall, on each pass clearing away another layer. Then…

“I think I’ve got something here!” exclaimed the Australian. He directed his video camera at the spot. Drifting silt clouded the image, but not enough to stop Nina’s heart from thumping at the sight. “Looks like a way in.”

On the screen, a passageway disappeared into darkness. It was hard to judge scale, but if the temple had been constructed the same way as its counterpart in Brazil, the opening was roughly four feet across.

“I’ll use the secondary vac to dredge it out,” said Trulli. “Give me a few minutes.” One of the Sharkdozer’s arms extended, but instead of using the large bucket at the end to clear the obstruction, a narrow metal pipe extended from beneath it, probing the opening and sucking away the deposits inside.

Chase leaned over Nina’s shoulder to examine the 3-D display, his cheek almost touching hers. “You know… if this temple has the same layout as the one in Brazil, that passage might lead right into the altar room. There was a shaft at the back, but it had been filled in with rocks.”

Nina gave him an accusing glance. “There was? Why didn’t you tell me?”

“I didn’t have time! You know, with the whole imminent death thing.”

“A priest hole,” said Kari thoughtfully. “A secret exit.”

Trulli worked for several more minutes before retracting the arm. “I’ve cleared out as much as I can. Jimbo, warm up Mighty Jack!”

While Trulli backed the Sharkdozer away, Baillard brought his own submersible closer, parking it at the edge of the expanded depression around the north wall. Once in position, he announced, “Evenor, I’m releasing the ROV… now.”

All eyes went to the Atragon’s 3-D display, which switched from the ghostly monochrome of the LIDAR system to a full-color video image as Mighty Jack left its cage and headed for the temple. The little robot didn’t have the laser imaging system of its parent vessel, but it still had stereoscopic cameras. As it entered the opening, the tight confines of the passage beyond gave a vertiginous sensation of speed. “God, it’s like attacking the Death Star,” Chase observed.

Mighty Jack proceeded down the passage. There were still clumps of sediment along its floor, but Trulli had cleared enough for the ROV to pass. The tension in the control room rose as the robot advanced, to find…

A blank wall.

“No!” Nina gasped, disappointed. “It’s a dead end!”

The ROV turned left, then right, its spotlights finding nothing but solid stone. “What do you want me to do?” asked Baillard.

Nina was about to tell him to bring the robot back out when Chase interrupted, leaning close to speak into her headset’s mike. “Jim, this is Eddie. Can that thing go straight up?”

“Yes, sure. But-”

“Do it.”

After a moment of hesitation, the ROV rose cautiously towards the ceiling…

And kept going.

“Whoa!” said Baillard, rotating Mighty Jack to examine the side walls as the robot ascended. “How did you know that was there?”

“Just a hunch,” said Chase, grinning at Nina. “Watch out, though. There might be traps on the way up.”

She gently swatted him away from her headset. “Eddie, somehow I doubt there’s been anybody maintaining this temple for the past eleven thousand years.”

“I dunno, those mermaids are tricky bitches…”

Nina smiled, then turned her attention back to the screen. Baillard angled the camera upwards as much as he could, the shaft taking on perspective.

“I see something,” he announced. A dark line on the wall of the shaft came up fast, a shimmering distortion…

The image suddenly rolled, tipping back to the horizontal. One of the stone walls filled the screen. “Jim!” Nina called. “What happened? Did you hit something?”

“Just a second…” The robot slowly turned, the image still shaking queasily. Nothing was visible except the walls. “Okay. I guess that’s as far as Mighty Jack can go.”

“What do you mean?” Kari demanded. “Is it stuck on something? Have we lost the ROV?”

Baillard almost laughed. “Not at all. It’s just that… well, Mighty Jack’s only designed for use in the water. So you’ll need some other way to explore from this point on.”