Ferdinand lifted his face.

John was staring back at him, wearing a frightened smile. “Is…is it over?”

Ferdinand glanced out the porthole. The jagged fissure had reached within a yard of Neptune’s steel legs.

The quake shook with one last fierce rumble, then died away.

“That was too close,” John said.

Ferdinand nodded.

Over the radio, a squelch of static erupted. “Neptune, this is Perseus. Is everyone okay in there?”

Ferdinand stumbled to the transmitter, relieved that Brentley had safely weathered the quake. “All clear, Perseus. Just shaken up.”

“Glad to hear it! I’ll pass the news topside.”

“Thank you, Perseus.”

Ferdinand slumped in his seat. He turned to John. “Let’s hope that doesn’t happen again.”

John nodded. “Oh, yeah. I don’t have enough clean pairs of underwear.”

Ferdinand smiled weakly. He willed his heart to stop pounding. That had been too damn close.

6:22 P.M., Nan Madol, Southeast of Pohnpei Island

“Kaselehlie!” The small dark-skinned boatman greeted Karen in native Pohnpeian, smiling broadly. He was bare-chested and wore loose shorts that hung to his knobby knees. Behind him, the ruins of Nan Madol spread in a series of man-made islets toward the open sea. “Ia iromw?”

“We’re fine,” Karen answered, bowing her head slightly. “Menlau. Thank you. I called earlier today about a day rental of one of your rowboats.”

The man nodded vigorously. “The scientists. Yes, I have better than a rowboat.” He turned and led them down a short stone quay of black basalt to a pair of long canoes. “Much better. Smaller. Travel the canals better. Faster.” He motioned with a hand, sweeping it back and forth.

Karen eyed the worn fiberglass canoes dubiously. They hardly looked seaworthy enough even for the shallow canals. “I guess these will be fine.”

The boatman’s smile widened. “I have map. Two American dollars.”

Karen shook her head. “I have my own. Thank you.”

“I act as guide. Seven American dollars an hour. I show you all the sights. Tell you stories.”

“I think we can manage on our own. Besides, we have our own guide.” She nodded toward Mwahu.

The boatman looked crestfallen and waved them toward the canoes.

“Menlau,” she said, passing down the quay, leading the others.

Jack kept pace with her and mumbled, “A real capitalist, that guy.”

At the two canoes, Miyuki joined them. She studied the sun low on the horizon. “Let’s get going. We don’t have that much daylight left.”

Karen sighed. She knew her friend still fretted over Mwahu’s earlier warning. “Miyuki, you’re supposed to be a computer scientist. Since when do you believe in ghosts?”

“Looking at this place, I’m beginning to waver.” Overhead, a pair of fruit bats swept past. Distantly, the calls of birds sounded lonely and lost. “It’s so creepy here.”

Karen nudged one of the boats. “Well, you’re right about one thing. We should get going. Why don’t you and Mwahu take this one? Jack and I will take the other.”

Miyuki nodded and climbed into the canoe as Mwahu held it steady. Then the islander clambered skillfully in afterward.

“Are you sure you can lead us to the grave of your ancient teacher?” Karen asked Mwahu.

He bobbed his head.

Satisfied, Karen turned to the other canoe. Jack already sat in the stern. She carefully stepped into the canoe’s bow end and picked up a paddle. “Everyone ready?”

There was a general sound of assent.

“Let’s go!”

Karen dug in her paddle, and the canoe slid smoothly from the dock. Ahead, Miyuki and Mwahu led the way, paddling under the basalt entry gate of the ruins. Past the gate, the breadth and scope of the site opened before them. High palaces, low tombs, great halls, miniature castles, simple homes. All framed by watery canals. Mangrove trees and thick vines were draped throughout, creating a maze of water, stone, and overgrown vegetation.

Karen paddled silently, while Jack guided the canoe with considerable skill. He cut the boat around a narrow corner. They were traveling through what was known as the “central city” of Nan Madol. The canals here were less than a meter wide, the basalt islets tightly packed around them. Jack continued to follow Mwahu’s zigzagging course.

“You’re good at this,” Karen said as Jack swung the canoe smoothly under a bridge of vines and lilting white flowers. “SEAL training?”

Jack laughed. “No. It’s a skill learned from years of float trips down the rivers and creeks of Tennessee. It’s like riding a bike. You never forget.”

Facing forward, Karen hid her smile. It was good to hear Jack laugh. She settled back as they paddled slowly toward the heart of the ruins, crisscrossing from canals dark with deep shadows to sunlit channels. Some paths were so choked with overhanging ferns and mangrove boughs that she wished they had a machete. Yet at all times the stacks of basalt logs surrounded them, prismatic crystals glowing in the late afternoon sunlight. Walls towered up to thirty feet, only broken by the occasional window or doorway.

Finally, the canals widened. To the right, an especially huge basalt island appeared, a great structure built upon it. Its walled fortifications towered forty feet, a monstrous construction of logs and gigantic boulders.

“Nan Dowas,” Karen said, pointing at it. “The city’s central castle.” They glided along the fern-choked coastline of the wide island. Doorways opened into the structure, some intact, some collapsed.

“It’s huge,” Jack said.

They passed another entrance guarded by a large basalt boulder. Nodding toward the structure Karen explained, “It’s one of the entrances to the subterranean tunnel network. The passages here have never been fully explored and are considered feats of engineering. In fact, further west, there’s an islet named Darong with a man-made lake atop it. At the bottom of the lake is a sea tunnel that leads to the reef’s edge. It allows fish to travel into the artificial lake, maintaining its stock.”

“Impressive.” Jack dug in his paddle and turned the canoe away from the castle as Mwahu led them to a more open section of the city. They floated over coral reefs rich with anemones and colorful fish.

From here the imposing sea wall of basalt pillars and slabs came into view. Taller monoliths dotted its lengths, silent stone sentinels staring out to sea. Periodically, narrow spaces opened: gates to the ocean beyond.

After a few minutes of gliding along the walls, they cut back into the maze of islets. Soon Karen found herself drifting down a narrow canal, the walls festooned with tiny pink and blue blossoms, scented not unlike honeysuckles. She inhaled deeply.

A slap drew her attention around. “Bees,” Jack warned.

Karen smiled. “Leave them alone and they’ll leave you alone.” She felt something crawling on her arm and jumped—then realized it was Jack tickling her with a long blade of dry grass. “Funny,” she scolded him.

He tossed the blade away with a look of total innocence.

Karen faced forward, paddle across her knees. At least Jack seemed to be coming out of his funk.

Behind her, he spoke up, more serious. “Do you have any idea where this guy is taking us?”

She fished out her map and spread it on her lap. She eyed the islets around her, then bent over the map. “Hmm…”

“What?”

“I can guess where he’s leading us. There’s a sacred place near here.” She looked up as they rounded a tall promontory.

Ahead appeared a huge island, even larger than Nan Dowas. But instead of a single castle, the artificial island held a sprawling complex of buildings and crumbled walls.

Mwahu aimed his canoe toward its shore.

“Pahn Kadira,” Karen said, naming the place. “The ‘Forbidden City’ of Nan Madol.”

Mwahu glided into the island’s shadow and beached at a low spot. He waved them over.

“Why forbidden?” Jack asked.

“No one can say. It’s a term passed from generation to generation.”

Jack guided them toward the bank, pulling alongside the other canoe. “It seems we’re about to find out.”

Jack held the boat steady while Karen climbed ashore. As she joined Miyuki and Mwahu, Jack roped the canoes to the bole of a lone mangrove.

“This way,” Mwahu said softly. His gaze flickered across the deep shadows as he led them along a thin trail through a dense accumulation of ferns to an arched entry.

Beyond the gate, a wide stone plaza opened. Grasses and flowers sprouted between the cracks. To the left, the remains of an ancient fortification lay toppled. To the right stood low-roofed buildings with narrow doorways and small windows. Ahead, splitting the plaza in half, was a thin carved channel, an artificial creek forded by a wide bridge.

“It is so hot,” Miyuki said. She wiped her face with a handkerchief, then pulled out a small umbrella. Pohnpei was known for its frequent showers, but today the sky had remained cloudless. Miyuki opened her umbrella and sheltered in its shadow.

As a group, they crossed the long plaza.

Karen would have liked to explore the surrounding sites, but Mwahu continued on single-mindedly, looking neither right nor left. He led them across the bridge and toward a tall building on the far side. It rose ninety feet above the plaza, with two low wings sprouting off from the central keep.

Karen stepped up next to Mwahu. “Is this the tomb of Horon-ko?”

Mwahu did not answer. He made a vague motion to remain silent. Reaching the wide entrance to the central keep, he paused and bowed his head, his lips moving silently.

Karen and the others waited.

Finished with his prayer, Mwahu took a deep breath and led them inside, with Karen right behind him.

The entrance hall was dark and refreshingly cool. As Karen entered she was struck by how clean the air smelled. No mustiness, just a hint of salt and dampness. The short passage led into a cavernous chamber. Their footsteps on the stone floor echoed off the heights. She fumbled through her pack and removed a penlight. The thin beam pierced the darkness, splashing across the featureless walls and roof.