Poseidon's Arrow

“The fault line should be on a bearing of zero-six-five degrees,” Summer said.

Dirk engaged the submersible’s electronic thrusters and propelled them on the northeast heading. Through the yoke, he could feel a strong bottom current sideswiping them. “The Agulhas Current is humming today. Like to take us to Australia.”

The powerful Agulhas flowed down the east coast of Africa. Near the southern tip of Madagascar, where Dirk and Summer were diving, it converged with the East Madagascar Current and streams from the Indian Ocean to create an unpredictable swirl.

“We likely drifted a considerable amount during our descent,” Summer noted, “but if we hold to the heading, we’ll still cross the fault line.” She pressed her nose against the bubble and scanned the lightly undulating seabed passing beneath them. After several minutes, she spotted a slight, but distinct, ridge. “That’s our uplift.”

Dirk ascended slightly and positioned the submersible in a hover ten feet above the ridge. “Ready for video.”

Summer powered on a pair of external cameras mounted to the submersible’s skids, then checked the feed on a monitor. “Cameras are rolling, marking start,” she said. “Take us down the line.”

Dirk thrust the submersible forward, following the ridge in the seafloor. They were working in concert with a NUMA research ship that had surveyed the area previously with a multibeam sonar system, examining an active fault line off the Madagascar coast in hope of better predicting how earthquakes create tsunamis. The submersible’s video would give the shipboard geologists a baseline reference for the area. The submersible would then be sent back to bury small sensors that would precisely record seismic activity.

The project required an interdisciplinary mix of talents that appealed to both siblings. With Dirk educated in marine engineering, and Summer specializing in oceanography, both twins had inherited their father’s love of the sea. They had joined Pitt at NUMA only a few years earlier but soon reveled in the opportunity to travel the globe to solve the sea’s mysteries. Their work was made all the better when the three of them could collaborate on a project, as they had recently in Cyprus, where they’d discovered a trove of ancient artifacts related to Jesus.

“Passing kilometer number eight of the subsurface ridge that will never end,” Dirk said two hours into their trolling. The constant bucking of the current was taking a toll, and he could feel his arm muscles begin to tighten.

“You’re not getting bored already?” Summer asked.

Dirk stared at the unchanging brown bottom that scrolled beneath them. “It’d be all right with me if someone imported a whale shark or a giant squid to the neighborhood.”

They tracked the uplift for another hour before Dirk became concerned about their battery reserves.

“Fighting the current has put an extra strain on the motors. I suggest we think about breaking off the run soon.”

Summer checked their distance covered. “How about another six hundred meters? That will put us at an even twelve thousand.”

“Deal.”

Completing that last remaining stretch, Dirk pulled the submersible to a halt while Summer turned off the video cameras. He began purging the ballast tanks to ascend when Summer motioned out the front bubble window.

“Is that a shipwreck?”

Beyond the effective range of the exterior lights, Dirk saw a faint object. “Could be.” He released the ballast pump and thrust the submersible forward.

A towering black mass gradually emerged, taking on the distinctive shape of a ship’s hull. As they drew closer, the rest of the vessel took form, sitting upright on the bottom and appearing remarkably undisturbed. Maneuvering just a few feet off the seafloor, they approached amidships, inching close to the mystery vessel. The red paint that covered the hull reflected clearly under the submersible’s lights, detailing every rivet and seam.

“She looks like she just went under,” Dirk said. He drove the submersible up the side of the hull and above the deck rail. There, they spotted three large open hatches on the forward deck. Dirk piloted the submersible toward the bow, skimming over cargo compartments filled with nothing but seawater. They peered down the sharp prow, detecting no damage around the bow. They turned back and surveyed along the starboard rail to the rear superstructure, where they ascended several levels to the bridge. From just a few feet away, they peeked through the intact windows at an empty control station.

“Looks like the helm was stripped of most of its electronics,” Dirk said. “That makes a good argument for her being scuttled.”

“Somebody call Lloyd’s of London,” Summer said. “I’ve never seen such a pristine shipwreck. She must have sunk recently.”

“No more than a few months, judging by the minimal sea growth.”

“Why would somebody scuttle a perfectly good freighter?”

“Hard to say. It’s possible she was under tow, headed for a refit, and sank in poor weather.” He checked the status of their battery power. “It’s about time we head topside, but let’s see if we can get a ship’s name.”

He guided the submersible around the superstructure to the stern and descended past the aft rail. A bent flagpole hung forlornly over the rail, its former colors long since vanished. When they were twenty feet off the ship, he turned the craft to face the freighter’s transom and adjusted their height so the lights would shine on the ship’s name.

“Well, I’ll be,” he said in a low voice. “She was scuttled after all.”

In front of them stood a blank wall of red bisected by a thick horizontal band of rust where the ship’s name and home port had once been posted. But somebody had intentionally ground away the name and covering paint, sending the freighter to the lonely depths in total anonymity.

44

THE NUMA RESEARCH SHIP ALEXANDRIA WAS stationed four miles away when the submersible broke the surface, and Summer radioed for recovery. As the submersible drifted with the current, she and Dirk passed the time studying the dusty brown shores of southern Madagascar, which seemed to rise and fall across the choppy sea.

The Alexandria arrived promptly, its turquoise hull, like all the ships in the NUMA fleet, sparkling under a sunny sky. A brawny man with a thick mustache and even thicker Texas accent directed the retrieval of the submersible onto the ship’s aft deck. Jack Dahlgren opened the vessel’s rear-mounted hatch and welcomed Dirk and Summer to the fresh air. “Y’all have a good swim?”

“We certainly did,” Summer said, holding up a portable hard drive. “We obtained excellent footage of the uplift and should be able to identify some prime insertion points for the ground sensors.” She climbed past him, scurrying to locate the ship’s marine geologist so they could jointly review the seabed footage.

“I take it that means an immediate prep for another dive?” Dahlgren asked with a long face.

Dirk patted him on the shoulder. “I’m afraid it does, my friend.”

Dirk assisted Dahlgren in removing several heavy sets of battery packs that powered the submersible, swapping them with freshly charged replacements. While they worked on the aft deck, a large patrol boat appeared from shore. As the boat loosely circled the Alexandria, two casually dressed occupants on its open bridge studied the research ship with a look of displeasure. When the Alexandria moved off-site, the patrol boat ran back to shore.

“I wonder what those boys are up to,” Dahlgren said.

“They didn’t exactly look like government officials.” Dirk gazed toward the receding boat, and shoreline beyond. “I thought the coast around here was pretty well an empty desert.”

“A small freighter came cruising through while you were down. It appeared headed to shore, so there must be some sort of harbor nearby.”

They finished swapping batteries and completed an extensive predive safety check before tracking down Summer in one of the ship’s labs. She had assembled a crate of tiny battery-powered ground sensors that would track tremors and movements in the fault line. Each was contained in a stainless steel canister that sprouted a