Kari brought up a map on the screen. “Captain Perez now thinks we should be able to get the Nereid to within three miles of the search zone before the river becomes too narrow to navigate.”

“That’s a lot closer than we thought,” said Nina, examining the map. “How long will it take to get there?”

Perez looked at the controls. “We’re doing twelve knots at the moment, but I doubt we’ll be able to hold that for much longer. In about another fifteen kilometers we’ll be heading up a tributary with much tighter bends, and we’ll have to slow down. But we made good time yesterday, so… If the river’s with us, it could be as little as four hours.”

“Well before nightfall, then,” said Nina. “So what’s the plan when we get there?”

“That’s up to you,” Kari said.

“Me?”

“It’s your expedition.”

Nina shook her head. “No, Kari, it’s definitely yours! I’m just, I dunno, an adviser.”

Kari grinned. “Then advise me! What should we do when we arrive? Do we wait on the boat until tomorrow so we can have a full day’s exploration-”

Chase clapped his hands. “Sounds good to me! Julio’s cooking again, right?”

“Or do we take the Zodiac and start the search for the city as soon as we arrive?”

All eyes were upon Nina. “Er… we… take the Zodiac?” she finally decided.

“Aw, bollocks,” Chase complained, not meaning it.

“Good,” said Kari. “In that case, we’d better get prepared. I don’t want to waste any time.” She closed her laptop and left the bridge.

“You bloody workaholic,” Chase said to Nina after she had gone. “We could have had another nice night on the boat if you weren’t in such a rush to find this place! You know, it’s been there for ten thousand years, it’ll still be there tomorrow.”

“Oh, admit it,” she replied. “You’re just as curious about finding it as I am!”

“Okay, maybe I am. But,” he said, his tone becoming more serious, “You’ve got to promise me something.”

“What?”

“If we find this place-and I think we will; you obviously know what you’re doing…”

“Thanks.”

“Then I want you to promise me that you’ll keep calm, okay?”

“What do you mean?”

“I mean, I don’t want you to get all excited, go running off-and then fall down a pit, or set off a giant boulder that goes rolling after you, or something.”

“You’ve been watching too many movies,” Nina teased. “As you said, it’s been there for ten thousand years. Even if the place was crawling with booby traps, which is highly unlikely, the mechanisms wouldn’t be working after all this time. Any moving parts would have seized up or rotted away by now.”

“You know what I mean,” said Chase, slightly exasperated. “I just don’t want you to get hurt, okay?”

“Okay, okay. If we see any spear traps, I’ll stay out of the light.”

“Promise?”

“Promise.”

“Good.” Chase grinned. “By the way, that was officially the worst Harrison Ford impression in the world. Ever.”

“Oh, I’d like to hear you do any better,” said Nina. “With your Cockney accent.”

“Cockney!” Chase pulled a face of exaggerated outrage. “Bollocks to that! I’m not a Cockney, I’m a Yorkshireman! Ought to throw you in the bloody river for that. Hmm…” He looked at her calculatingly.

“Oh no you don’t,” said Nina, backing away.

“Time for a swim, Doc!”

She shrieked and fled, Chase pursuing her with a maniacal laugh.

With a last throaty rumble, the Nereid’s engines fell silent. “This is as far as we can go,” said Perez.

According to the GPS, they were just under three miles from the search zone; slightly closer than Perez’s prediction, but his instincts about the navigability of the river were correct. Not only were the serpentine twists of the narrowing tributary too tight for the lengthy Predator to negotiate, but the sluggish water was increasingly clogged with debris. Despite Perez’s best efforts to avoid them, several fallen trees floating in the water had banged alarmingly against the hull.

Nina looked through the bridge window at the jungle. It appeared much the same as it had during the rest of the voyage… but now that the banks were so much closer, it seemed to loom higher. More menacing, almost alien.

“We’ve got just over five hours until sunset,” said Chase. “Enough time to let us get the lie of the land. Hell, maybe we’ll be lucky and walk right into this place.”

“That’d be nice,” Nina said. She had spent most of the day inside the air-conditioned cabin, finding the atmosphere outside more humid and stifling than ever.

“Is the Zodiac ready, Mr. Chase?” asked Kari.

“All set. Just add water.”

Everyone returned to their cabins to collect their packs and equipment. Nina decided to carry as little as possible, sticking to basics like water, food and insect repellent on the grounds that between them Chase, Castille and di Salvo would have all the survival gear the team could need. But she paused before picking up her pack, staring at the Atlantean sextant arm on the desk. She touched the pendant around her neck, thinking for a moment.

“What the hell,” she decided, picking up the metal bar and wrapping it in its cloth.

Kari tapped on the half-open door. “Can I come in?”

“Hi! Of course.”

“You’re bringing it with us?” asked Kari as Nina put the artifact in her pack. “I thought you were going to leave it in the safe.”

“I was, but…” Nina shrugged uncertainly. “I don’t know, I just thought it might be useful. If we get lucky and find something, maybe I can compare any text with it, be sure we’re in the right place.”

“I think we are. I know we are.”

A piercing whistle cut through the air. “Oi! Doc! You ready?” Chase called from outside. “Shift your arse!”

“Coming!” Sharing an amused roll of the eyes with Kari, Nina hoisted the pack over her shoulder and left the cabin. Chase was waiting for them.

“Don’t you ever get hot in that thing?” Nina asked, prodding the sleeve of his leather jacket.

“Hey, if it’s good enough for Indiana Jones… Anyway, I only sweat when I’m hassled.”

“And how often do you get hassled?”

“Since I met you, a lot more!”

The Zodiac was loaded, Perez and Julio lowering it into the river. The water was thick with algae and dead leaves, the boat making more of a turgid splat than a splash. Chase poked at the surface with a stick, sweeping rotting vegetation aside to check the color of the water.

“Top tip of the day,” he told the rest of the party, “don’t go in the water. And definitely don’t drink it either.”

“But surely the water should be perfectly fine,” declared Hamilton, who had donned a rather vivid red shirt in contrast to the earth tones worn by every one else. “It’s fresh rainwater, with no man-made pollutants!”

“Well, stick a straw in the river and suck away if you want. But you can clean out the bog afterwards.”

Hamilton looked confused. “Bog? Are we going into a swamp?” Chase sighed and shook his head.

They boarded the Zodiac, Chase sitting at the rounded bow while Castille worked the outboard motor. Nina and Kari sat facing each other on the boat’s fat inflated sides behind Chase. Di Salvo, Hamilton and finally Philby clambered aboard behind them. There were no seats, but those packs containing camping gear-Chase had decided to prepare for any eventualities-served as substitutes.

There was one pack that nobody wanted to sit on, however. Although it was closed, it was obvious from its angular bulges that it contained guns.

“Okay,” said Chase once everybody was settled, “all aboard the Skylark!” He waved to Julio, who untied the ropes. Castille started the outboard, which rasped and burbled into life. He guided the Zodiac carefully around the flank of its parent craft, then revved the engine and started the boat on its journey upriver.