Nina and Kari joined him in one corner of the room. At floor level, right where the two walls met, was a small vertical slot. It wasn’t much of an opening-but compared to the precise joins of the other blocks, it was clearly a deliberate feature rather than poor workmanship. “What’s inside?” Kari asked.

“No idea-it’s too small to get my hand into. Nina, you’ve got nice dainty little fingers-have a root around.”

“And I’d like them to stay nice,” Nina complained, but she knelt by the slot anyway. “Oh God. I just hope there’s not some finger-chopping thing or a scorpion inside…”

She warily slipped her fingers between the blocks. A little more… more…

Her fingertip touched something. She flinched, afraid it was a hair-trigger that would drop the spikes onto them. But the trio remained unimpaled.

For now.

“What is it?” asked Kari.

“There’s something metal in here.”

“A switch?”

“I don’t know… hold on.” Nina tried to slide her fingers around the obstruction. “It could be.”

Chase leaned closer. “Can you pull it?”

“Let me,” said Kari. “Nina, you should wait in the passageway. Just in case something goes wrong.”

“If it doesn’t work, then we’re going to be dead soon anyway,” Nina said. “You two get out of the chamber. Go on!” she added, before either of them could object. She took several deep breaths as they backed through the entrance to the chamber. “Okay. Here goes…”

She wrapped her fingers around the metal, paused for a moment to wonder what the hell she was doing, and pulled it.

Clink.

The hanging framework of spikes remained still.

Another, louder clink of metal came from the stone door. Nina exhaled loudly. “I think it worked…”

“Get out of the room,” Chase ordered, waving Kari to stay back as he walked to the door. Nina gratefully obeyed. He braced himself, then pushed. The door swung open, heavy stone rasping over the floor. Another dark passage lay beyond.

“You did it!” Kari cried.

“Nice work,” said Chase. “But we really need to shift-we’ve only got twenty-one minutes left.”

“We’d better get a move on then.” Nina patted Chase’s arm as she passed him. “And you were right about the lateral thinking.”

“We make a pretty good team, don’t we?” he said. “You’ve got the brains, I’ve got the brawn, and Kari’s got…”

“The beauty?” suggested Nina. Kari smiled.

“I was going to say agility, but yours works too.” He took the light from Nina. “Okay. So we beat the three challenges. Now what?”

“Now we put the artifact back where it belongs, then get the hell out of here,” Nina said, advancing down the passage.

Castille glanced nervously to the west. The sun had long since dropped behind the high canopy of trees, but pinpoints of bright light still made it through the dense foliage.

It was very close to the horizon, though. And the sky overhead was rapidly turning a deeper blue as dusk crept in…

He looked back at the temple entrance. The square of darkness was devoid of any movement, as it had been from the moment the glow of Chase’s flashlight had disappeared about forty minutes earlier.

“Hurry up, Edward,” he said to himself.

“Wh-what if they’re dead?” Philby asked, sweat covering his panicked face. The three prisoners were on their knees outside the elders’ hut, several hunters encircling them.

“They’ll make it,” Castille said, wishing he felt as confident as he sounded.

An unexpected harsh crackle cut through the mutterings of the Indians and the chatter of birds. It was coming from the abandoned packs.

“Survey team, do you read me? This is Perez. Do you read me? Over.”

The Indians reacted with predictable shock, jumping into defensive positions and aiming their weapons out past the perimeter of the village as if expecting an attack.

“Survey team, come in, come in, over.”

“If we can answer him, he can call in the helicopter,” di Salvo said under his breath. “With some support.”

“And guns!” Philby added, almost hopeful.

“If we can persuade them to hand us the radio,” said Castille. The Indians had now worked out where the sound was coming from, and were cautiously investigating the packs, prodding them with their spears.

“Survey team, I don’t know if you can hear me…” One of the tribesmen jabbed Castille’s pack, momentarily muffling the transmission. “…got company. I can hear at least one chopper, maybe two, approaching my position. They’re not ours, I say again, they are not our helicopters. Please respond.”

“Military?” Castille asked, concerned.

“I would have been told if they were planning any jungle operations,” replied di Salvo.

“Merde.” Castille had a horrible idea who might be in the helicopters. “Agnaldo, try to get them to bring us the radio. We need to-”

One of the Indians pulled out the walkie-talkie. Perez’s voice was now clearer. “Survey team, I see one of the choppers! It’s-Jesus!”

A piercing screech of static blasted from the speaker, the Indian dropping the radio in fright. Philby looked between Castille and di Salvo in confusion. “What just happened? What was that?”

Castille gave him a grim look, twisting to look in the direction of the river. A few seconds later, a sound like a distant clap of thunder reached them. “That was the Nereid exploding,” he said.

“What?”

“It’s Qobras. He’s found us.”

Chase checked his watch. “We’ve only got eighteen minutes left.”

“Then we need to keep moving,” said Kari. She took out the sextant arm. “Find where this needs to go.”

“Maybe we could just leave it here and pretend we put it back,” Nina said, not entirely joking.

“I think they might check,” replied Chase sarcastically.

“Well, it was a thought… Oh.”

They had reached the end of the passage.

Chase lifted the flashlight. Even its bright beam was almost lost in the huge room beyond.

“The Temple of Poseidon,” Nina whispered.

Chase stared in awe. “Bloody hell.”

By Nina’s estimate, the great chamber was two hundred feet long, half the length of the entire building, and nearly as wide. The vaulted stone ceiling, wreathed with gold and silver, rose like a cathedral roof, supported along its length by buttresses at the sides of the vast room. In each alcovelike space between the buttresses was a statue, glinting with the unmistakable color of gold. There were dozens of them, ranks of unimaginable riches.

But they were nothing compared to what had seized the attention of the three explorers. At the far end of the chamber, stretching to the very highest point of the ceiling nearly sixty feet above, was another statue.

Poseidon.

“My God,” said Nina as she walked towards it, any concerns about traps completely banished from her mind. “It’s just as Plato described it…”

“There was the god himself standing in a chariot, the charioteer of six winged horses, and of such a size that he touched the roof of the building with his head,’” recited Kari alongside her.

“You’d get a few quid for that on eBay,” Chase remarked.

“Those must be the hundred Nereids,” said Kari, ignoring him and pointing at a circle of much smaller statues around Poseidon’s chariot.

“Doesn’t look like a hundred to me,” Chase said as they headed for the giant statue.

“I bet there’s sixty-four of them,” said Nina. “In base eight, that would be the number as important as a hundred in base ten. Plato was using a word translated from a different numerical system, but the actual number it represented was different-”

“I count seventy-three,” interrupted Kari.