“Secure the hatch!” he cried.

He immediately dropped down the interior ladder. The emergency dive alarm rang out an instant later, sending the crew scurrying to their stations. In the engine room, a massive clutch was engaged, killing the diesel engines and transferring drive power to a bank of battery-powered electric motors. Seawater began to slosh across the forward deck as Catalano sealed the conning tower hatch, then descended to the control room.

Normally, a well-trained crew could crash-dive a submarine in under a minute. But since it was loaded to the gills in transport mode, there was little the Italian sub could do quickly. With agonizing leisure, it finally sagged under the surface nearly two minutes after Conti had detected the approaching aircraft.

His boots clanking on the steel ladder as he descended into the control room, Catalano turned and scurried forward to his emergency dive station. The clatter of the diesel engines had fallen quiet as the sub converted to battery propulsion, and the crew mirrored the silence by speaking in hushed tones. The Barbarigo’s skipper, a round-faced man named De Julio, stood rubbing sleep from his eyes as he asked Conti if they’d been seen.

“I can’t say. I didn’t actually see the aircraft. But the moon is bright and the seas are relatively calm. I am sure we are visible.”

“We will know soon enough.”

The captain stepped to the helm station, scanning the depth gauge. “Take us to twenty meters, then full right rudder.”

The submarine’s chief steersman nodded as he repeated the command, eyeing the gauges before him as his grip tightened on a large metal steering wheel. The control room fell silent as the men awaited their fate.

A THOUSAND FEET ABOVE THEM, a lumbering British PBY Catalina flying boat released two depth charges that whirled toward the sea like a pair of spinning tops. The aircraft was not yet equipped with radar; it was the RAF plane’s rear gunner who had spotted the milky wake of the Barbarigo, angling across the rippled surface. Thrilled with his find, he pressed his nose against the acrylic window, wide-eyed, as the twin explosives splashed into the sea. Seconds later, two small geysers of spray shot into the air.

“A bit late, I believe,” the copilot said.

“I suspected as much.” The pilot, a tall Londoner who wore a clipped mustache, banked the Catalina in a tight turn with all the emotion of pouring a cup of tea.

Dropping the charges was something of a guessing game, as the submarine had already disappeared from view, though its surface wake was still visible, and the plane had to strike quickly. The airborne depth charges activated at a preset depth of only twenty-five feet. Given enough time, the sub would easily dive beyond their range.

The pilot lined up for another run, tracking a marker buoy they had released ahead of the initial attack. Eyeing the remnants of the sub’s fading wake, he gauged the vessel’s unseen path, then gunned the pig-bellied Catalina just past the buoy.

“Coming up on her,” he told the bombardier. “Release if you’ve got a target.”

The bombardier for the eight-man crew sighted the sub and flipped a toggle switch, releasing a second pair of depth charges stowed under the Catalina’s wings.

“Depth charges away. Spot-on this time, I’d say, Flight Lieutenant.”

“Let’s try one more for good measure, then see if we can raise a surface ship in the vicinity,” the pilot replied, already banking the plane hard over.

INSIDE THE BARBARIGO, the twin blasts shook the bulkheads with a deep shudder. The overhead lights flickered and the hull groaned, but no rush of water penetrated the interior. For a moment, the explosion’s deafening roar seemed to be the worst consequence, ringing in each crewman’s ears like the bells of St. Peter’s Basilica. But then the ringing was overpowered by a metallic clang that reverberated from the stern, followed by a high-pitched squeal.

The captain felt a slight change in the vessel’s trim. “Fore and aft damage reports,” he yelled. “What’s our depth?”

“Twelve meters, sir,” the pilot said.

No one in the control room spoke. A cacophony of hisses and creaks permeated the compartment as the sub dove deeper. But it was the sound they didn’t hear that prickled their ears—the splash and click of a pair of depth charges detonating alongside the submerged vessel.

The Catalina had dropped wide on its last pass, its pilot guessing north while the Barbarigo veered south. The last muffled explosions barely buffeted the submarine as it plunged beneath the reach of the depth charges. A collective sigh was expelled as, to a man, the crew realized they were safe for the time being. Their only fear now would be if an Allied surface ship could be summoned to renew the attack.

Their relief was cut short by a cry from the steersman.

“Captain, we seem to be losing speed.”

De Julio stepped close and examined a bank of gauges near the pilot’s seat.

“The electrical motors are operational and engaged,” the young sailor said, wrinkling his brow. “But I show no revolutions on the driveshaft.”

“Have Sala report to me at once.”

“Yes, sir.” A sailor near the periscope turned to retrieve the Barbarigo’s chief engineer. He’d taken only two steps when the engineer appeared in the aft passageway.

Chief Engineer Eduardo Sala moved like a bulldozer, his squat frame churning forward in a blunt gait. He approached the captain and stared at him with harsh black eyes.

“Sala, there you are,” the captain said. “What is our operational status?”

“The hull is secure, sir. We do have heavy leakage at the main shaft seal, which we are attempting to stem. I can report one injury, Engineer Parma, who fell and broke his wrist during the attack.”

“Very well, but what about the propulsion? Are the electric motors disabled?”

“No, sir. I disengaged the main drive motors.”

“Are you crazy, Sala? We were under attack and you disengaged the motors?”

Sala looked at the captain with contempt.

“They are irrelevant now,” he said quietly.

“What are you saying?” De Julio asked, wondering why the engineer was evasive.

“It’s the screw,” Sala said. “A blade was bent or warped by the depth charge. It made contact with the hull and sheared off.”

“One of the blades?” De Julio asked.

“No . . . the entire screw.”

The words hung in the air like a death knell. Absent its single screw propeller, the Barbarigo would be tossed about the sea like a cork. Its home port of Bordeaux suddenly seemed as far away as the moon.

“What can we do?” the captain said.

The gruff engineer shook his head.

“Nothing but pray,” he said softly. “Pray for the mercy of the sea.”

PART I

POSEIDON’S ARROW

1

JUNE 2014

MOJAVE DESERT, CALIFORNIA

IT WAS A MYTH, THE MAN DECIDED, AN OLD WIVES’ tale. Often he had heard how the desert’s broiling daytime temperatures gave way to freezing cold at night. But in the high desert of Southern California in July, he could testify, that wasn’t the case. Sweat soaked the underarms of his thin black sweater and pooled in a damp mass around his lower back. The temperature was still at least ninety degrees. He glanced at his luminescent watch, verifying it was indeed two in the morning.

The heat didn’t exactly overwhelm him. He’d been born in Central America and had lived and fought guerrilla campaigns in the region’s jungles his entire life. But the desert was new to him, and he simply hadn’t expected the nighttime heat.