Behind the powerboat a wake of white foam spread like an elongated arrow on the glassy green water. The overnight rains had ended and the morning haze had burned off. The sun beat mercilessly. The breeze of their twenty-knot speed kept the four people on the boat from wilting in the heat.

Had Mercer been able to forget what lay at the end of this journey, he would have cracked a beer and enjoyed himself.

He stripped off his shirt, leaving him in just shorts and sneakers. He watched with fascination as the unusual coast-line rolled by. It was tough to imagine that the immense body of water wasn’t a natural formation. Lake Gatun, in fact all of the Panama Canal, represented an unprecedented triumph of human engineering over a nearly insurmountable obstacle. Geology had separated the Atlantic from the Pacific three million years ago and now they were connected across a lake floating eighty-four feet above sea level. That the canal was nearly a century old made it that much more impressive.

From the boat’s speeding deck, Mercer found himself hard pressed to find evidence of the lake’s unnatural birth. Farther on, past Gamboa where the canal narrowed toward the Gaillard Cut, its man-made nature revealed itself, but here it looked like any other lake in the world. It wasn’t until he looked closely at the islands that he could tell they had once been hilltops and the lake’s meandering shore the flanks of mountains. There was little evidence of erosion and only a few small sections of beach. Also, the vegetation covering the islands contained few aquatic plants. There were no marshes or wetlands, as he’d expect to see. The jungle simply stopped at the water’s edge where it ran out of soil. Outside the shipping lanes, he occasionally saw the tips of old telegraph poles sticking from the water’s surface, birds perched on the rotting wood. They were remnants of the old rail line that had been submerged when the lake formed.

He imagined that this is what the world would look like if the polar ice ever melted. The endless parade of ponderous freighters and tankers only enhanced that impression. It was easy to think that the last remnants of humanity were borne on their great hulls like a flotilla of modern-day Noah’s Arks out of some post-apocalyptic science-fiction scenario.

Juan Aranjo, Carmen Herrara’s brother, kept them well outside the buoys that marked the shipping lanes as they sped away from Limon toward the Pedro Miguel Lock. He spoke no English and seemed content in silence rather than engaging Lauren in conversation.

Lauren’s cell phone chimed.

She waved for Mercer to answer it. She and Tomanovic were checking over the equipment she had rented at Scubapanama, the country’s premier dive shop, where she was known.

He dug it out of her knapsack. “Hello.”

“Mercer, it’s Roddy.”

“Are you guys out of the house?”

“We just got to our new hotel. The kids are getting spoiled by your generosity. Even Miguel wasn’t so disappointed about you leaving him behind when he found there is a pool here. And Harry’s already working his way through the mini-bar.”

Mercer smiled at that image. “Have you heard anything from Foch? There was no answer when I tried calling him from Limon.”

“No, I haven’t,” Roddy said. “A couple of his men made sure we got to the hotel safely but I haven’t spoken with him. However, I did get a call this morning from a friend of yours. Maria Barber.”

That was the last person Mercer had ever expected to hear from again. “Really? What did she say?” A thought occurred to him and concern crept into his voice. “Hold on, how did she know to call you? She thinks I’m in D.C.”

“Don’t worry. I asked her the same thing. She tried your home in Washington and then took a chance calling me. She said you’d told her about me when you two had dinner.”

Mercer had worked to purge the whole ugly night from his memory so he didn’t specifically remember that part of their conversation. “What did she want?”

“Besides you?” Roddy teased, then turned serious. “She claims she has some information about her husband’s death.”

“Did she say what it was?”

“No, she wanted to talk to you in person. I told her you were going out on Gatun with my brother-in-law and couldn’t be reached. I have her number if you want to call her.”

“How did she sound?”

“Like she’d started her morning with a couple of Bloody Marys.”

Mercer’s mouth turned downward. “Keep the number. I’ll call her when we’re finished.” Or maybe he wouldn’t call her at all. It was unlikely she had any pertinent information. She was probably just drunk and lonely, and looking for affection. His pity for her went only so far.

“Where are you guys?” Roddy asked.

“According to the chart Juan showed me, I think we just passed Barro Colorado Island. We’re going to hold up near here until late afternoon. I don’t want us hanging out near the Pedro Miguel Lock longer than necessary.”

“Good idea. The Canal Authority hasn’t banned pleasure boats from approaching the locks, but with the heightened security they could ask you to leave if they get suspicious. Call me when you’re done.”

“Will do,” Mercer said and killed the connection.

Ten minutes later, Juan Aranjo cut away from the shipping buoys and motored toward the shore, tucking his boat into an isolated bay far from where they could be seen. He took them under an overhang of thick palms to hide them from aerial observation and the noontime sun. After killing the engine, he tossed a small anchor over the side. The jungle was a riot of bird calls.

Lauren declined his offer to use the cabin so Juan went below to sleep through the afternoon. Like soldiers anywhere in the world, Tomanovic found a corner to curl up in. The gentle sway of the boat and the shaded warmth lulled him immediately to sleep.

“All your equipment check out?” Mercer asked Lauren quietly.

“We’re good to go.” If she was nervous about diving near the lock it didn’t show in her voice. Lauren gave him a level gaze. “Can I ask what really happened to you at the mine?”

Mercer’s stomach clamped. All morning he’d convinced himself that he could put the incident out of his mind. The frantic preparations—getting the dive gear, picking up Tomanovic and meeting up with Juan—had kept him occupied. Now that they had a couple of hours with nothing to do but wait, he’d hoped the memories would remain suppressed. Lauren’s question brought the whole thing back in brutal clarity.

“Why do you ask?” he hedged.

“Something tells me that the description you gave us in Roddy’s kitchen wasn’t the whole story.” She paused. “From the bedroom Carmen let me use I could hear you moaning and thrashing in your sleep.”

Mercer wasn’t comfortable giving voice to what bothered him. He’d witnessed so much ugliness and death that it would take a lifetime to talk it out. Instead, he steadily purged it himself, banishing it to the darkest corners of his memory where only nightmares dwelled. He knew that it was an ill-advised attempt at denial, but somehow it seemed to work.

She’d asked the question without guile, not understanding how much he didn’t want to recall the torture. As he took a minute to gather his thoughts, Mercer slowly realized he was grateful. Somehow she’d sensed that this incident wasn’t going to go away without help.

“This is going to sound weird, but he took something from me.” He chuckled. “And not just my watch.” Their eyes met. “He killed me, Lauren. I was dead. He did something with his needles that stopped my heart from beating. I could feel it lying in my chest, the rhythmic thumping I’d always taken for granted was gone. I could feel that I was dead.”

Lauren went pale. She didn’t know what to do with that information. It was far beyond anything she’d ever heard before.

Mercer continued, “I went someplace that no one is supposed to return from. And you know what? It wasn’t anything like what you’ve heard. I didn’t hover over the room looking down at my body. I was still there on a slab with a madman standing over me. There was no heavenly glow, no friends to guide me to the afterlife. There was nothing except the inevitability of oblivion. I don’t know what to think about that.”

After a moment, Lauren said, “You weren’t dead.”

Although she spoke with absolute conviction, Mercer recognized the empty assurance. Her words rang of a childhood spent at Sunday school and of regular church attendance. “Please, Lauren. You weren’t there.”

“There is no way he could stop and then start your heart with a couple of acupuncture needles. It’s impossible.”

“Are you stating scientific fact or defending your faith?” It sounded harsher than he intended. He regretted it and was relieved when she let it pass.

“How do you know your heart stopped? Did you really feel it in your chest or were you aware because there was no pulse in your ears?”

Mercer had to think about that. The torture had been so vivid in his mind, but that detail eluded him.

Lauren’s next question added to his confusion. “Do you remember hearing anything when you say your heart was stopped?”

“I don’t think so,” he replied after a moment. “Sun wasn’t talking or anything.”

“There’s your answer. Sun didn’t speak because the acupuncture needles paralyzed your inner ears, more specifically the tiny hairs in your cochlea that turn sound vibrations into a signal your brain can recognize. When he blocked those nerve impulses, he prevented your brain from feeling the rush of blood near your cochlea. Your heart was pumping just fine—you just couldn’t tell.”

“But . . .” Mercer began to protest then stopped himself. Her explanation was simple and logical. It made more sense than Sun having the ability to arrest his heartbeat. And yet he knew deep down that something fundamental had happened to him, something that he couldn’t name. So what if Sun had tricked him into believing he’d died? The feelings his torture created in Mercer were no less crippling.

He felt like he stood on a precipice, wanting to take the leap that might help him find what Sun had taken, while part of him desperately wanted to pull back. He knew the void was too great. It was full of too many monsters. Too much pain. He wasn’t strong enough to push past his own doubts.

He couldn’t look Lauren in the eye when he lied. “Maybe you’re right. Sun didn’t take anything from me. His little hoax, making me think he’d stopped my heart, fooled me into giving it to him.”

Lauren reached across the deck to take his hand. “Whether he took something or only made you think he did, you have to believe that you are whole now.”

“You’re not going to let me get away from this, are you?”

“No. For two reasons. I’m about to put myself in danger and I need to know you’ll be there to back me up.”

“If I couldn’t support you, I wouldn’t let you dive today. You have to know that.” Mercer had never meant anything more in his life. He would not let her down.

“All right.” She nodded. “Good.”

“And the second reason?”

“I’ll tell you that one after the dive.” While her voice sounded like she’d let this matter drop, her eyes did not. She smiled to dissolve the severity of the moment. The slight gap between her teeth acted like a counterpoint to the flawlessness of her beauty. To Mercer it only made her more attractive.

She rolled her arm to look at the matte-finished dive watch she wore instead of her regular Rolex. “Since we’ve got some time before we go into the water, I’m going to follow Vic’s lead and catch some sleep. Last night wasn’t one of the more restful I’ve had. Are you going to be okay?”

Mercer rummaged through a satchel he’d brought and extracted the leather-bound Lepinay journal. He held it up. “I still haven’t read this damned thing. I think now’s a perfect opportunity. But do me a favor. If you ever meet Jean Derosier, the guy who sold it to me, don’t tell him I took it out on a boat. He’d kill me for exposing it to the elements.”

“Deal.” She stretched out on the bench seat with a bundled dive bag as a pillow and seemed to slip away after a few seconds.

Mercer watched her sleep. He both marveled at and was frightened by her instincts about what Mr. Sun had done to him. He wondered if it was female intuition or if it physically showed on him. He hoped the former but suspected the latter.

He cracked open the journal. The smell of the old pages was strong, a scent that Mercer always associated with knowledge. Without an English-French dictionary, he could only get a vague sense of some of what Godin de Lepinay wrote more than a century earlier about his travels in Panama. Yet he was confident that he would understand more than Bruneseau when he had looked through it in Paris. Rene read it with the eyes of a spy.

Mercer’s saw it the way the author intended—as an engineer.

Three hours later, with the sun sinking toward the west, Mercer closed the book. Reading the faded script had started a dull ache in his temples. Before he woke the others he washed down a couple of aspirin with water from a bottle. Baron Lepinay wrote in a rather flowery style, odd for a man of science, and Mercer was sure he’d missed a lot of the subtlety in the text. Also, Lepinay compared geologic and geographic features in Panama to others he was familiar with in France. He’d written things like a particular hilltop reminded him of Mont Mouton. Mercer couldn’t know if there was even a place called Sheep Mountain in France or what it would look like.

Still, the journal didn’t contain a single reference to missing treasure, Incas, or anything else Liu Yousheng had shown interest in. It was little more than a travelogue, with details on how Lepinay would build a lake-and-lock canal. For Mercer it was a remarkable historic artifact, but it offered nothing about their present situation. The only thing even remotely close was a passage about visiting an extinct volcano in the north of Panama that sounded a bit like the one above the River of Ruin, including a lake and island. Lepinay didn’t have a geologic background and didn’t know that similar volcanic lakes dotted the globe. He was especially impressed with the smoothness of the lava tubes that had once belched molten rock from deep in the planet’s interior.

Mercer returned the journal to his bag, feeling a nostalgic twinge for the first time he’d explored such a feature at a volcano in Hawaii. He was sure that if Liu knew its contents, he wouldn’t have bothered trying to steal it in Paris. He had a perverse desire just to mail it to Hatcherly’s president with his compliments.

Putting aside his dismay, he called out to Lauren and Vic. It was time to get going. Juan lumbered up from the cabin, his shirt unbuttoned down to his navel so that his sweaty belly spilled over his belt line. He went forward to haul up the boat’s anchor.

“Oh, hey,” Lauren exclaimed after wiping sleep from her eyes. “Did you find anything in the journal?”

“Not one damned thing,” Mercer said. Lauren’s expectant look dimmed. “It was interesting from a certain point of view, but I couldn’t find anything that would compel Liu to send gunmen to steal it. Maybe he really is interested in canal history.”

Lauren shot him a doubtful look. Mercer shrugged as if to say anything’s possible.

Juan switched on the fuel pump and keyed the ignition. The motor came to life. For the remainder of the trip down the canal, Tomanovic and Lauren had to remain out of sight. The idea was that Mercer was to act like a photographer who’d hired a local’s boat to take pictures of the ships using the lock. To enhance the deception he still had the camera and lens he’d brought to the River of Ruin.

Lauren and Vic ducked into the cabin to don half-millimeter Henderson microprene body suits, more as camouflage than thermal protection, as Juan pulled them away from their secluded anchorage and headed back for the main channel. They passed a couple of excursion boats lined with camera-wielding tourists in addition to the normal parade of oceangoing transporters. The sun continued its dive for the horizon. Its reddish glow mirror-flashed off the water whenever a wave turned to the proper angle.

Exiting Lake Gatun, they started down the narrower reach toward the Gaillard Cut and the Pedro Miguel Lock. Because the exclusionary marker buoys for the big ships left only tight lanes along the banks, Juan kept his craft tucked to the right shore, on the opposite side of the canal from Gamboa. Beyond the wide twists in the waterway, Mercer could see the looming massif of the continental divide. The closer they got, the narrower the canal became and the more the landscape revealed its artificial nature. The hills that once fell in lazy slopes to the water had been partially leveled and stepped back so they resembled the terrace farms Mercer recalled from trips to Asia and Africa. Jungle vegetation was just now reclaiming the land. This was the latest in a century-long effort to stem the landslides that had plagued the canal since the moment the first steam shovels began tearing open the passage.

One hundred and five million cubic yards of dirt had been excavated from the Gaillard Cut alone, fully half of all material unearthed for the canal project. An early description of the sheer volume of rubble removed to build the Panama Canal stated that if it were compacted into a column with the base the size of an average city block, it would climb to 100,000 feet. Or put another way, the overburden would fill a string of railcars long enough to circle the globe—three and a half times. As Juan Aranjo’s boat motored farther into the cut, Mercer felt that no guidebook comparison could possibly depict the awesome scale of the project. He’d seen many of the world’s engineering marvels, the Great Pyramids, the Coliseum in Rome, the Golden Gate Bridge, Hoover Dam, the Channel Tunnel. All of them paled next to this.

Towering to their right, they passed what remained of a particular hill that had been blasted to the exact shape of the step pyramid at Saqqara. Then they reached the actual continental divide. Mercer was astounded to think that he was in the middle of a mountain range that stretched from the tip of South America all the way to northern Canada. Walls of andesitic basalt rose in stepped-back cliffs five hundred feet above the placid water. These were the remains of Gold Hill and Contractor’s Hill, the highest mountains near the canal and yet the lowest the early engineers could find when they surveyed the route. Holes had been drilled into the rock and reinforced concrete plugs inserted to add stability, and still there was evidence that rockslides continued to occur. The canal was a little more than six hundred feet wide and it seemed the tops of these stone massifs weren’t much wider, looming like the sides of the artificial canyon this was.

From the deck of the small boat, he had to tilt his head all the way back as they motored between the shadows of these man-made cliffs. The recent rain had saturated the veneer of soil on top of the hills, so water cascaded down the faces of the hills in white horse-tail streaks.

“Pretty amazing, huh?” Lauren asked from the entrance to the cabin. The black microprene suit clung to her body like a second skin.

Mercer had to force himself not to stare. “I was just thinking that when they were digging the cut, the temperature must have been about a hundred and twenty degrees.”

“The heat was about that bad, yes, but what bothered them most were the landslides. Months of digging could be refilled in just one avalanche, burying steam shovels and train tracks and men. I read it was so unstable that not only would mud slide into the dig, but at times, the bottom of the cut actually bulged upward because of the weight of the mountains next to it.”

Mercer visualized the titanic weight of the two hills pressing into the soft substrata and causing an upthrust between them, like pinching two ends of a balloon to expand its center. It was rock mechanics on the largest scale.

They watched in silence for a few minutes. Lauren finally spoke. “On the drive over, you were kind of vague about what Vic and I are looking for down there.” Behind her, the Serb used a whetstone on the blade of his dive knife. “Care to give me something specific?”

“I’m not sure,” Mercer said. “Roddy told us that all the ships that suddenly went off course had been delayed coming out of the west lane at Pedro Miguel. He and the other pilots didn’t report anything wrong with the ships’ steering. No one had tampered with the auxiliary controls or anything like that. Roddy and I think that maybe something was attached to the hulls of these ships to cause the course changes.”

“A submersible?” she asked doubtfully.

“I know it sounds farfetched, but how would you go about changing the direction of a twenty-thousand-ton ship? Remember, none of the vessels that went off course were PANAMAX ships. They were smaller freighters passing through the canal at night. This would give a submersible the room to maneuver and, depending on how it was designed, the power to alter the course of such a vessel. The sub could be moved into position as soon as the lock doors open. The ship is then held up for a few minutes while the sub is attached. And when the time is right, it uses its engine to nudge the freighter off course.”

“Why go through all that when it would be cheaper, and easier, just to pay off a couple of canal pilots to cause these accidents?”

“If Liu does close the Panama Canal the subsequent investigation is going to be massive. He can’t risk those pilots being questioned and can’t kill them either because that would be more suspicious. Also, by staging a string of such strange incidents he’s created a pattern that would explain away an explosives-laden ship he intentionally rams into the canal’s bank.”

Lauren’s brow creased as she considered Mercer’s explanation. He could tell she was reluctant to believe his idea. Her nod was more to say that he should go on than that she bought the scenario. He saw that their relationship had suffered in some fundamental way because of his reaction to the torture. He didn’t know what he could do or say to reassure her that he was still thinking clearly. Nothing, probably, until he did finally come to grips with what Sun had done to him.

“I’ve got to hand it to Liu,” Mercer continued, putting aside her uncertainty. “He’s damned thorough. He’s planned dozens of moves ahead, and remains flexible enough to react to our presence. Every contingency I can think of, he’s already considered. Any investigation into a catastrophic explosion will show that American-trained canal pilots have a history of screwing up. Following the trail of gold he’ll pay to Panama only leads to a mine that looks legit. If the canal is closed for a couple of years, the fact that Hatcherly Consolidated has container ports and bought a rail line and has almost finished an oil pipeline will seem like a case of right place right time, not something deliberate.”

“It all seems so convoluted.”

“It is, and that’s the beauty of it. It’s too complex to be plausible and yet there’s no other explanation.” He paused. “Anyone with enough motivation and explosives could blow up anything in the world. The trick is getting away with it. That’s what separates a lunatic from a calculated terrorist. We’re not dealing with suicidal fundamentalists. These are rational people who want to survive the attack and enjoy their rewards. That’s why it has to be so complex. Liu’s got this operation planned to the final detail and is weeks, maybe only days from pulling it off.” His eyes bored into hers. “Lauren, do you realize that if I hadn’t been suspicious about how Gary Barber died the investigation would have ended in the jungle with that police officer you don’t like. No one would have any idea that a Chinese company, ostensibly owned by their government, was about to shut down the Panama Canal in such a way that the United States would be unable to react.”

“Señor,” Juan Aranjo interrupted.

Mercer looked up. Like an oasis of technology in the middle of a primeval jungle, the Pedro Miguel Lock lay just ahead. Their little boat was now on the Pacific side of the continental divide so the terrain had flattened into gentle slopes covered in golden grass and palms. On the east bank a shantytown of corrugated buildings abutted the chain-link fence that stretched along this section of the waterway. Laundry swayed from lines stretched across the squatters’ village, and behind it was the railroad and the trans-Panama highway. Closer to the side-by-side locks sat a mooring site for the small boats pilots used to reach the ships they were to guide, several parking lots, and two long warehouses. These structures were maintenance sheds for the electric trains that towed vessels through the locks. The trains ran on tracks laid on the edges of each thousand-foot-long lock chamber and on the sixty-foot-wide wall that divided the two concrete basins. Up to six of these engines, called mules, were needed to guide their unwieldy charges into and then out of the locks so that neither was damaged. It was up to the canal pilots to coordinate a ship’s own motive power with that of the mules, and to maintain proper tension on the heavy towlines to see the vessel transit the lock safely.

A tanker had just passed out of the right lock, giving Mercer a view down the length of the chamber to the tops of the mitre doors that held back Lake Gatun. They closed inward in the shape of a flattened V so the angle helped spread the tremendous load they held at bay. From Roddy he’d learned that the doors were sixty-five feet wide, seven feet thick, and were hollow so that they floated to make opening them easier. Each individual gate weighed upwards of seven hundred tons. And here at Pedro Miguel, both lock chambers had two sets of doors on the downstream end so that if one were somehow broached, there wouldn’t be a catastrophic failure that could conceivably drain the lake.

From the low vantage of Juan’s boat, Mercer couldn’t accurately gauge the scale of this amazing system, nor could he see the mile-long Miraflores Lake beyond. On the far end of that lake was a pair of double locks built in stair-step fashion that raised or lowered ships a total of fifty-five vertical feet from the level of the Pacific Ocean.

As he watched, the freighter in the left-hand lock began to rise perceptively, levitating as gravity dumped eight and a half million gallons of water into the chamber. In just a few minutes, the level within the lock reached that of the cut and the massive doors swung outward. The mules heaved on their lines to pull the ship out. Once the steel hawsers were cast away from the vessel, white water erupted at its stern as its huge propeller powered it away.

Mercer looked down at Lauren once again. “We’re here. We’ll wait for twenty minutes or so for the sun to go down a bit more and then put you and Vic in the water.”

“Okay.”

Juan knew his role as tour guide and began pointing out features for Mercer to shoot with his camera. Not that there was any film in it. He tried to determine if there was any unusual activity going on at the lock, but all seemed normal. A continuous procession of ships lumbered by. None of them were cruise liners or PANAMAX freighters because it was getting late and the sun would be down by the time they reached the Gatun Locks on the other side of the country.

Mercer dutifully acted like he was burning through pictures, all the while his stomach tightened with tension. He hated that he was asking Lauren and Vic to do something of which he himself was incapable. It wasn’t in his nature to let others put themselves at risk, but this was too important to trust his rudimentary diving skills. All during the wait he checked on her as much as he dared without acting too unusual. Her outward calm didn’t seem to be hiding anything more than a natural sense of anxiety.

After twenty-five minutes, Lauren said the angle of the sun was right for their dive. The surface of the canal was a flickering sheet of reflected sunlight, as if the water had turned to flame.

“A cargo vessel is about to come out of the right lock,” Mercer informed her out of the corner of his mouth. “Its bulk will prevent anyone at the lock from seeing you scramble over the side as long as no one’s on the ship’s wing bridge. I’ll keep watch, and as soon as I say go, get yourselves into the water.”

Vic stood behind Lauren on the short stairs rising up from the cabin so he could help her maneuver off the boat with the big air tank on her back. A belt of lead weights draped from her waist and a buoyancy compensator hung from her neck. Lauren and the Serb had already pulled on hoods that matched their dive suits and had their masks in place. Both carried their flippers, which they would slip on their feet once they were safely under water.

Taut muscles in Lauren’s arms and shoulders made slender crests in her suit. From behind the mask, her eyes were steady. “When water flushes through the lock’s access pipes,” she said, “we’ll face some pretty tough currents that’ll cut into our bottom time. Even at minimal consumption these tanks have a maximum of sixty minutes of air. Scubapanama didn’t have any of the bigger ones I wanted.

“Three-quarters of an hour. Gotcha.”

She touched his arm. “I mean it, Mercer. Expect us in forty-five minutes, but if we’re not back in sixty, we ain’t coming back. There is no leeway in these numbers. If you don’t see us in one hour, you won’t see us at all. Promise me you’ll get your butt out of here.”

Mercer held her gaze for a second, nodded, then raised his camera to study the freighter through the long lens.

The ship’s captain and canal pilot must have stationed themselves on the far side of the vessel because only a pair of Panamanian soldiers acting as guards stood at the wing-bridge rail. One waved down at the little boat and Mercer turned the camera away, not wanting to give them any reason to remain. The rest of the four-hundred-foot ship appeared deserted.

Mercer watched the two bored troopers surreptitiously and the instant they moved away from the rail to return to the air-conditioned comfort of the bridge, his voice cracked, “Now!”

Tomanovic moved so fast he was nearly carrying Lauren and her sixty pounds of gear as he lunged up the steps. When he reached the gunwale, he grasped her around the middle and spun around so that when he tumbled over the side he shielded her body with his. They hit with a small splash and a boil of bubbles. A few moments later, two gloved hands rose from the water and gave the divers’ circular okay signal by touching thumb to index finger.

The hands vanished and the water churned slightly as the two finned away. Mercer pulled Lauren’s Rolex from his pocket and noted the time. Forty-five minutes, she’d said. They’d be back up at seven-eighteen.

The sensation was like falling into a bottomless bathtub because the water was blood warm. Lauren twisted in liquid space and tucked her knees to her chest to slip on her flippers before adding air to the buoyancy compensator. She and Vic found their equilibrium at the same time and both slid toward the surface to give Mercer a signal that they were all right. She bled a little air from the vest, allowing her to drop back into the void. They leveled off at forty feet, deep enough for much of their exhausted breaths to dissipate. She immediately equalized the pressure in her ears and behind her face mask. Through the murky water, Lauren could feel the throbbing engine and thrashing propeller of the freighter passing abeam of them.

Because she was used to ocean diving, it took her a few moments to get used to the difference in buoyancy the freshwater gave her and its silty taste. Visibility was pretty bad, maybe twenty feet, but would give her enough warning if there was anything in the water with them. There was little current this far from the locks, yet Lauren was prepared for the suck of water once one of the chambers began to fill.

Together, she and Vic began swimming in easy strokes toward the lock.

Her PADI instructor once told her that scuba was the sport for the lazy. Do nothing fast and don’t waste energy you might need later. It was advice she’d never forgotten.

Using just the strength in her supple legs, she kicked through the milky emerald water toward the distant concrete structure. Vic stayed at her side. Above them, the setting sun had turned the surface into a distant plane of crimson mercury. Below lurked an impenetrable gloom.

Mercer’s assurance that he was okay rang in her mind. She wouldn’t have gone in the water if she didn’t believe him. He was up to this mission, yet she still harbored a lingering doubt. He had been damaged in that torture chamber in some way he refused to acknowledge. It was a male thing, she felt, the unwillingness to admit pain. She’d seen it in her father, her brothers, and all during her military career, especially in Kosovo. Like most men, Mercer would stupidly spend days or weeks working it out himself rather than save time by talking.

Lauren wanted to help him. She remembered him talking about his childhood in Africa and knew he was capable of expressing his feelings. If she could—

Focus, damnit, she admonished herself, concentrating on her breathing. She had her own priorities right now.

After ten minutes of swimming, a shadow formed in front of her and Vic. Like coming across a sunken building, they approached huge walls of cement that quickly filled their vision. The front of the twin locks.

Vic jerked a thumb downward. Lauren nodded and the two sank farther into the abyss, coming up on the bottom at fifty-five feet. The floor of the canal was barren stone, swept clean by the remorseless tidal action of the locks filling and draining. It looked like a desert. Not a piece of trash, leaf, or stick in sight. The bottom of the locks sat on a massive concrete foundation ten feet above them. The steel doors were like those guarding a giant’s castle, utterly impregnable.

Flanking each set of doors were culverts formed within the cement, each bigger than a subway tunnel. These eighteen-foot-diameter pipes were the inlets through which water entered the lock. Feeding off them inside the lock’s walls were fourteen evenly spaced branches, each large enough to accommodate an automobile. These cross-passages stretched under the chambers themselves, and from them a total of seventy separate stem valves rose into the floor of the lock to evenly distribute the flow of water. The apertures in the lock’s floor in which the stem valves sat were ostensibly the smallest component of the whole mechanism and yet each was four feet square. All this piping could fill a 110,000-square-foot lock at a rate of two feet a minute. The billions of gallons that drain from the canal each year are replaced by seven feet of annual rainfall recharging Lake Gatun through the Chagres and other rivers.

Lauren hung suspended, mesmerized by the scale of what she was seeing. Age had darkened the concrete to a dull black, but the main feeder pipes were darker still, somehow malevolent, like haunted caves from a child’s nightmare. Despite the warm water, a chill ran up her spine and she whirled around, certain she was being watched.

Vic signed if she was all right and she acknowledged that she was. Her heart refused to slow and her breathing had accelerated. Again, she looked around. This time she caught a flicker of movement. Something was out there, another patch of darkness that wavered just beyond her view. She strained to see it, beaming her dive light in its direction. Nothing.

And then it came, resolving out of the murk, driving at them with the speed of a torpedo. Lauren got a brief impression of something silver before it was upon them. Even with the distortion of the water, it was at least eight feet long, powerful. She screamed into her mouthpiece, choking as she took a mouthful of water.

Vic’s hand lunged out to grip her shoulder, the touch enough to calm her. She blinked and realized their attacker was one of the tarpon that regularly got caught in the canal. The monstrous fish with its underslung jaw broke off its investigation and carved a tight circle around them to return to its hunt for a way out of the freshwater trap.

Lauren gave Tomanovic an embarrassed shrug. She readjusted the equipment that had shifted during her violent thrashing, making sure to note her air consumption. She compared her gauge to his. They were about even.

She looked back at the doors above them. It was hard to believe that something that large could move, yet they began to swing outward on hinges that weighed nearly twenty tons apiece. She could feel the movement of water as newly installed hydraulic rams forced them apart. A freighter or tanker would be drawn out from within the lock by the mules in just a few minutes. After that the doors would reseal themselves and the water within the chamber would drain into Miraflores Lake to lower the level for the next vessel coming up the thirty-foot stair.

Once that next ship was secured inside the lock and the doors closed, more than eight million gallons of water would be sucked through the intake pipes to raise it up to the level of the Gaillard Cut. The rush would create a surge more powerful than the worst rip current, a force that neither Lauren nor Vic could ever hope to fight. They’d likely be crushed within the labyrinth of tunnels under the lock and their corpses would eventually flush through the system like so much trash.

It was time to find the submersible.

Keeping the dive lights angled downward so they wouldn’t show to guards and workers above, they began scouring the bottom of the canal, looking for anything out of place, some piece of evidence that ships were being intentionally diverted by something kept here at Pedro Miguel.

If she and Vic couldn’t find evidence, they’d all have to rethink their theory about what Liu Yousheng and Hatcherly were trying to accomplish in Panama. Maybe this really was an elaborate smuggling scheme that had nothing to do with the canal. It could be that was what was bothering Mercer, Lauren realized. The idea that his theory could be tossed out the window and he wasn’t in on the investigation. From their first night on the River of Ruin, she knew he was a man who valued his self-reliance and she doubted he’d accept someone else’s conclusions without investigating on his own.

That wasn’t a male thing, she thought. That was a scientist thing.

Get your head back in the game, Lauren.

Above them, the long dark shape of a freighter pulling from the lock cut the scarlet reflection on the water’s surface. At its stern was an area of roiling vortices as its prop thrashed to build up speed. The hull was coated in barnacles that would drop off by the time the ship exited the Gatun Locks on the Caribbean side of the canal. Like the tarpon, they couldn’t survive long away from their natural saltwater environment.

The area she and Vic had to survey was much larger than Lauren had anticipated, and they had about ten minutes before they needed to retreat away from the intake tunnels for the duration of the filling process. The shaft of light from their dive lamps drilled a cone through the murk that only reached twenty-five feet. By swinging side to side, they cut fifty-foot swaths back and forth across the bottom, eyes tracking the sweeping beams. Vic pointed out a couple of industrial shapes, old equipment dumped off to the side of the lock gates, but nothing resembling a submarine or large underwater propulsion platform.

They’d been under for twenty-two minutes. By working from the lock back toward the boat, they shortened the distance needed to return, giving them another twelve minutes, including a couple for decompression. Lauren began to feel the futility of their task. There wasn’t anything down here. Mercer had been wrong. She didn’t think Roddy Herrara had lied about his accident to cover incompetence, but whatever happened to him and the other pilots who’d been fired had nothing to do with this lock.

Intent on their search, Lauren and Vic didn’t notice that the huge doors had closed. In another three minutes, the valves that controlled flow into the chamber would open. The lane they were cutting across the canal was just beyond the danger point where it would suck them in.

Neither did they notice that they were no longer alone.

Six amorphous shapes had moved into position above them, hovering like wraiths. At a signal from one of them, the six swooped downward in pairs, slicing through the water with the ease of sharks.

Lauren was the first to feel that something was wrong. It was the same sixth sense that had anticipated the tarpon charge. She flipped onto her back and gazed upward just as the frogmen plunged down at her and Vic. They wore black wet suits. Four held knives while the other pair carried spearguns. Bewilderment immobilized her for just a moment before her combat training took over.

She flashed her light at her dive partner, alerting him, then reached for the knife strapped to her thigh. If not for the spearguns, Lauren would have pumped more air into her buoyancy compensator and rushed past them for the surface. Instead she dumped air and raced for the bottom. Vic dove with her, swimming on his back so he could watch their stalkers. He held his knife across his chest.

The two divers with spearguns halted their advance twenty feet off the bottom, taking up positions that covered their partners as they continued downward in pursuit. The angle of the hunt took everyone closer to the locks.

Lauren found rocky footing on the bottom, bracing herself for the rush of attack. As the distance closed, she saw that the divers were Chinese. A frogman lunged from above and to her right, a straight slash that she easily ducked because her flippers were wedged against a stone and gave her leverage. She swept her knife as the diver tried to twist away. Dark blood bloomed in tendrils from the gash in the man’s calf.

She swam after him. The wound slowed the Chinese diver enough for her to catch up. Unable to brace her body for a killing strike with her blade, Lauren slashed again, opening another cut below the man’s double tanks. He spun over to face her. Lauren parried his attack, the clash of metal on metal muted by the water. With her free hand she reached for his dive vest, found what she wanted and with a squeeze filled the bladder of his buoyancy compensator like a balloon.

The frogman shot upward like a rocket, effectively taking him out of the fight for a couple of minutes. Lauren panted through her regulator.

Tomanovic struggled with the other three Chinese divers. One of them was bleeding from his shoulder while the other two looked unscathed. They had Vic surrounded in a cordon large enough for one of the divers above to shoot the Serb with his speargun. Lauren stroked into the battle, coming up behind one of the Chinese. She feinted going for his air hose, and when he moved to protect it she pumped up his vest so he began to rise uncontrollably. This time she stayed behind her victim as they ascended toward the two armed divers, using him as a shield.

Had the Chinese been a larger man, stronger, she wouldn’t have been able to smother his writhing attempt at escape. She held on tight, steering them to slam into his partner. The blow barely distracted either man, but Tomanovic used those few seconds to back away from the men who’d nearly captured him.

Lauren was now embroiled in a fight that resembled an aerial battle from World War One. She and the two frogmen tumbled through the water, pursuing one another and fleeing at the same time, defending and attacking in a ball that continued to shrink as each tried to get an inside advantage. The speargun had been nullified by the closeness of the combat, but knives flashed in the glare from the wrist lights the Chinese wore. It seemed no one could get the advantage to end the struggle.

The second speargunner watched the squirming ballet, waiting for an opening.

Vic launched himself from the bottom of the canal, ignoring the two divers who came after him. The speargun swiveled at him when he was spotted and still he kept coming. The Chinese diver steadied his aim, waited until his quarry was less than five feet away and pulled the trigger.

The Serb had judged his attack perfectly, his experience almost allowing him to read the mind of the man with the gun. He anticipated the shot by a full second. The arrow left a silvery streak of bubbles in the water as it slid along the length of his body, missing his torso as he contorted to the side. It continued harmlessly into the depths, its power diminishing by the drag of the water.

He swam past the gunman and somersaulted so that he hung inverted just above his target, keeping himself protected from the two divers with knives and at the same time giving him access to the speargunner’s air hoses. He sliced through the first one before the man realized Vic was still nearby. The Serb was just feeling for the second hose through the torrent of bubbles when an unimaginable pain exploded in his groin. A knife had been thrust nearly to the hilt from above. The blade entered below his testicles, ripping open his scrotum, cutting apart the large nerve cluster and scraping along the cradle of his pelvic bone.

He’d forgotten about the sixth diver, the one Lauren had launched toward the surface. He’d come back and exploited Vic’s vulnerable upside-down position.

Like an octopus that uses ink to escape a predator, the diver Vic had almost cut off from his air supply slipped away in the clouds of blood that pumped from the juncture of Vic’s legs. The man whirled, finding his adversary hanging limply in the water. Tomanovic was still alive but wouldn’t be for long as the lifeblood billowed from his body. Centering his aim, the Chinese frogman moved in to smash the butt of his empty speargun into Vic’s face mask hard enough to shatter the glass.

He’d clamped a hand over the air venting from his severed hose and was about to assist his partners still battling Lauren when a dull boom echoed through the water. He’d been stationed at the lock long enough to know what the sound meant. A ship was about to be lifted. The floodgates were opening to fill the chamber.

Disregarding the safety of his partners, he started swimming away as fast as he could, the two others holding formation with him.

In the odd rendering of time that is combat, the sixty seconds Lauren had been struggling with the other pair of divers had felt like an hour. As long as she stayed close to the speargunner, she wouldn’t be shot and the other with the knife couldn’t come in on her. Not that she’d gotten away unscathed. A couple of slices like razor cuts had split her suit and skin.

She felt the vibration pulse through the water and suspected what was about to happen. The other two knew it as well and tried to disengage. Rather than take the opening presented as the gunner turned to fin away, Lauren thrust-kicked after him, realizing for the first time how close they’d drifted to the locks.

All the Chinese were swimming toward the largest of the old machines dumped near the lock and the clarity of her adrenaline high allowed her to see that it wasn’t old at all, only painted oxide red. It was a modern diving bell, a pressurized chamber that permitted the frogmen to remain underwater for hours. The piece of junk next to it wasn’t an antique either. What she’d thought was a large-spoked wheel on one side of the truck-sized artifact was actually an enormous impeller on a specialized submersible. Mercer had been right!

The surge hit so strongly that it nearly stripped her mask over her head. In an instant she lost her forward momentum and was being drawn backward. The two Chinese were only a couple of feet ahead of her and they too were caught in the pull. The mechanical gates that controlled flow had cracked open. The current was already stronger than any Lauren had faced.

She couldn’t help looking back at the intake tunnel that was sucking her in like some horrible mouth. For a couple of seconds Lauren futilely resisted the force with her arms and legs. She swam faster than the Chinese divers and in a moment all three came abreast of each other. Yet it was a race to remain stationary. The gates opened farther and the current doubled, then doubled again. There was no way to resist it. They were caught, like flotsam in a whirlpool, and no amount of struggling could fight the pull. One of the frogmen dumped his weight belt in hopes he could float free. The second it took to slap at the buckle cost him several feet.

Lauren knew what she had to do.

They were twenty feet from the opening, accelerating toward it each second. There was no way she could prevent herself from going in. She could only hope to survive the ride. She committed herself by breaking her swim rhythm and grabbed for the diver next to her. Her grip slowed the beat of his leg. An instant of panic caused him to stop swimming altogether. Lauren torqued her body, bringing them broadside to the surge with him closer to the lock. Like a pair of kites caught in a sudden updraft they lost all control, flailing, pulled backward even faster than before. They smashed into the slower diver and all three tumbled in the jet of water. Lauren maintained her position behind them by holding on as tight as she could.

The rush of water sounded like a liquid hurricane. Lauren pressed her mask against the shoulder of the man in front of her and clamped her jaw on her mouthpiece.

Their target was eighteen feet in diameter but luck would have it that they were just to the right of the opening so they were drawn in at an angle. Lauren ducked her head as they were swept inside and felt the jolt as the first diver in line had his skull split open by the impact with the pipe’s concrete lip. The fountain of blood caught in the dive lights swirled in countless back-eddies.

Just one scrape against the lining of the tunnel would be enough to peel flesh down to the bone so Lauren fought the men, not the current, always keeping her body protected as they scuffed along the conduit. It was like holding on to a mattress while falling down a cliff. Disoriented by the endless tumble, she lost all sense of direction. The bubbles from her regulator danced like dervishes.

A light swept ahead and Lauren saw that amid the wild flurry of motion the draw of water being sucked down into the cross-culverts was pulling them across the tunnel. They’d already passed at least half of the fourteen inlets. It was only a matter of time before one of them pulled them in.

Like an animal working at a piece of meat, the torrent tossed them wildly and still Lauren managed to keep the two Chinese in front of her. Either the one in the middle, who she could feel was still breathing, didn’t understand her intentions or was too paralyzed by fear to resist. A roar like a subway rushing through the darkness filled her head. As they flipped again, the wrist light showed they careened scant inches from the left side of the pipe. Lauren had two seconds to brace herself. One of the ten-foot cross-culverts was just ahead and she knew this one was going to grab them.

When they hit the rim of the ninety-degree angle, the staggering collision blew her mouthpiece from her lips, her lungs emptying in a gust of pain. The corpse of the partially decapitated diver took most of the impact, the pressure of two people behind forcing the last of his blood to erupt from the ruin of his skull. The middle diver absorbed the rest of the blow, his rib cage shattering like glass.

Pressure held them to the concrete wall for an instant before the current yanked them in again. They dropped a short distance in a wrenching swoop as Lauren’s lungs ached to breathe. She couldn’t feel her mouthpiece but knew it was waving around her like a tentacle. The tunnel leveled out and an instant later they flashed beneath the first of the stem valves that fed water into the bottom of the lock chamber.

The water had lost part of its force, giving Lauren the courage to let go of the second corpse with one hand to snag her regulator. Her lungs were on fire. She could see the mouthpiece curling in front of her, but couldn’t coordinate her movements to grab it.

The end of her flipper hit the top of a lifter valve sunk partially into the floor of the tunnel and was torn off her foot. The hit sent a bolt of agony from her ankle. The last reserve of air she’d managed to hoard escaped in a silent scream. They streamed by another valve. Lauren could feel the counterforce of water entering the culvert from the second feeder tunnel located in the seawall dividing the two locks. Her forward progress slowed further. She lunged for the regulator again, forgetting all about her scuba training and the proper technique for retrieving a lost mouthpiece.

She needed air. The darkness spreading across her vision was in her head, not the surrounding water. Her lungs convulsed, a sharp draw that felt like her diaphragm had torn. She was about to drown.

One last desperate reach and she found the regulator. Gripping it tight, she shoved it past her greedy lips. The first taste of air almost made her cough. The second was like heaven.

Then the body, which had drifted below her, smashed into the third valve and the regulator was jerked from her mouth. She hadn’t realized she’d been drawing breath from the frogman’s tank. His body, and its life-giving regulator, vanished behind her and again she found her lungs nearly empty. The current pushed her closer to the tunnel’s ceiling.

She reached the center valve, banged hard against the edge of the opening with her air tank, and was suddenly floating in water that seemed as tranquil as a pond. She’d made it! She was inside one of the great lock chambers, eight hundred feet down its length from where she’d entered. Above she could see the silvery reflection of high-intensity lamps mounted above the facility. She just wanted to lay there and watch the dance of light on the underside of the water. Her back ached, her ankle screamed and she was so dizzy she could no longer think. Just lay here for a minute.

Like a warning from a friend who knew she’d forgotten something, her lungs convulsed again, a mild jolt that reminded her she hadn’t taken a breath in almost a minute. Without conscious thought, she stuck her arm straight behind her back, swept it forward and felt the air hose tickle along the inside of her arm. In a second she had the regulator in place and oxygen in her lungs.

It took her another minute to clear her head enough to check the level of air in her tanks. Amazingly she still had fifteen minutes. While it felt like hours, just eleven minutes had elapsed since she’d first spotted the Chinese divers. While the forty-five-minute deadline she’d given Mercer was upon her, she knew he’d be waiting for her for at least another twenty or twenty-five minutes despite his assurance he’d heed her order.

All she needed to do was swim up to the surface next to the ship she could sense looming above her, wait there until the lock doors swung open, and then swim back to Juan Aranjo’s little Wellcraft.

Simple.

She checked her depth. Thirty-eight feet. She had been working at a greater depth but took a guess that she’d purged the excess nitrogen from her blood by fighting the Chinese and slaloming through the culverts.

She began climbing upward, using her one remaining fin to maintain an easy pace, her mouth somewhat slack to allow the expanding air in her lungs to escape. There was a ten-foot gap between the side of the lock and the scaly hull of the ship going up the waterway. She held close to the cement, fearful of the spiky barnacles coating the ship like a jagged veneer of thorns. The vessel had probably languished in the Bahia de Panama for weeks or even months, accumulating such a thick skin of marine life, while its owner pulled together the money to pay for the transit. A not uncommon occurrence.

She had just passed the ship’s keel when she drew a breath that didn’t fill her lungs. She inhaled again and was left with a deep hollowness in her chest. Lauren knew what was wrong. Her tanks didn’t have fifteen minutes. They were empty; the gauge had stuck. She pushed harder for the surface, remaining calm, remembering her training.

As the sun set across the isthmus, the wind picked up in a sudden gust that slapped against the tired freighter in the lock. The ship’s pilot, on just his second solo run through the canal, hadn’t anticipated the dusk wind shears and the vessel got away from him, drifting closer and closer to the lock wall.

Lauren saw the gap of murky light closing as she swam for the surface. From ten feet it had shrunk to five in seconds and continued to dwindle. She was caught between the drifting freighter and a solid wall of concrete. She would reach the surface only to be pulped by the inevitable collision. She had one chance.

The air in her buoyancy compensator continued to haul her upward even as she stopped pistoning for the surface. Despite having empty lungs and tank, she had to sink below the ship if she was going to survive for a few moments more. The gap between ship and wall was down to four feet when she spilled the air from her vest. The change in buoyancy was immediate and she began to plummet, pulled downward by her weight belt and heavy dive gear.

Her hand scraped against the side of the ship, opening ragged cuts in four fingers before she could draw them back. Her lungs screamed for air. She could barely detect the difference in the darkness below her where she would clear the underside of the freighter’s keel. It seemed a thousand feet below her. Her tank bumped the wall, pushing her forward, and her hands brushed the hull again. More blood clouded the water.

The instant her feet sank under the bottom of the ship, she angled her body like a gymnast to get out of the way. The vessel slapped the lock two feet over her head. The metallic impact echoed in her skull like a great bronze bell, a sound that shook her bones and assaulted her hearing. Disoriented by the concussion, she continued to fall. She needed air, but she was too tired and too starved for oxygen to remember that she had to swim under the ship to reach the surface on its far side. Her backside hit the concrete floor and she fell back, her spine arched over her tank. Her vision became a kaleidoscope of swirling color as her brain slowly suffocated.

One point of light remained sharp amid the torrent of colors and she reached out for it, knowing in the back of her mind that she was grasping at nothing but a phantom. The brilliance faded, her brain unable to produce anything but monochrome. Her lungs pumped, but there was nothing there. Her chest and the air cylinder strapped to her back had equalized at empty.

“You were right about the submersible, Mercer,” she tried to say around her mouthpiece, letting in the first taste of the water that would kill her.

In her last seconds, the darkness that had filled her brain exploded into a dazzling incandescence before she could no longer stop her mouth from going slack and her lungs inflating.

It was a struggle to maintain the persona of a photographer. Mercer found himself increasingly looking at the watch and not pretending to shoot pictures of the locks at sunset. Ships continued to parade by. Juan Aranjo had settled himself on the stern bench seat, pulling his stained baseball cap low over his eyes. Though he didn’t have Mercer’s emotional investment, he kept shifting his position as if the nervous energy radiating off his passenger was a physical distraction.

Mercer drank through two liters of water in the first forty minutes out of sheer nervousness. Floodlights all along the lock chambers came on, bathing the area in a glow that flattened perspective. The water beyond the pools of illumination had grown inky.

As they waited, a group of men gathered at the end of the seawall dividing the two locks. The distance and the noise from the nearby ships made it impossible to hear what they shouted to the pleasure boat, but when Mercer turned the camera on them, their gestures made it clear. They wanted Mercer and Juan to clear out.

Ignoring their growing agitation, Mercer threw a wave and continued to pretend to take pictures of the ships. Lauren’s deadline passed. Mercer’s palms had gone slick and his throat dry. Another man joined the group. Unlike the workers in their overalls and hard hats, he was dressed in a shirt and tie. He carried a megaphone and his amplified voice boomed in Spanish.

Mercer touched his ear and shouted back. “No hablo.”

“You are no longer permitted in this area,” the man said in English. “Leave immediately.”

Mercer waited a minute before moving to the driver’s seat. He twisted the boat’s key in the ignition but didn’t turn on the fuel pump. The motor caught, ran for a few seconds, then sputtered to silence. He tried it three more times with the same result and threw up his hands in frustration. He turned to face the men on the seawall and shrugged his shoulders.

A rust-streaked grain carrier suddenly slammed against the cement seawall when the pilot misjudged a wind gust. The sound was like a cannon blast.

“We will send a pilot boat to tow you to Gamboa,” the canal worker shouted. He pulled the walkie-talkie clipped to his belt.

“Shit.” Mercer searched the calm water for any sign of the divers. Nothing.

It would take ten minutes for a launch to reach them and already Lauren and Vic were overdue. As a soldier, Lauren lived by the clock and had given a maximum time. He checked her watch. They’d been down for fifty-seven minutes. She’d made it clear that their absolute limit would pass in three more. Mercer’s heart began to race.

Nothing looked amiss at the locks, nothing to indicate that they’d been captured. The mules had tugged the errant freighter back to the center of the lock chamber. Lauren and Vic must be swimming back. If they ran out of air, all they had to do was surface. He studied the water in the fading light. There were no telltale trails of bubbles, no disturbances on the silky surface.

Up the canal, one of the pilot boats came to life. A moment later it pulled from its mooring and vanished behind an ore carrier that had just passed out of the locks. The divers had been down for more than an hour. Surely there was a couple minutes’ reserve. The launch appeared around the stern of the ore carrier, heading toward Mercer. “Come on, Lauren,” he breathed. “Just pop up, we’ll get you before they reach us.”

He had her Beretta 92 wrapped in a towel. It would buy a few more minutes, but he had to consider the consequences. If he took out the men in the launch, he and Juan couldn’t stay where they were anyway. The Canal Authority had stationed troops at the locks and the next pilot boat that came after them would bristle with automatic weapons. Mercer would only succeed in getting himself and Juan killed.

Sixty-seven minutes. Even if they had just remained motionless beneath the boat to conserve air, the two divers would have exhausted their tanks seven minutes ago. Any kind of exertion would have cut deeply into that time. More likely the tanks had gone dry a quarter hour earlier. Jesus, what had happened?

Frantic, Mercer called out Lauren’s name. Maybe she had gone to shore. Shadows had lengthened and merged so he could barely see the darkened banks. The only sound he heard was the approaching burble of the motor launch. He shouted again, his voice pinching in his throat as the sickening truth crushed down on his organs. He fought not to let the idea take root in his mind. It wasn’t possible.

The launch was fifty yards away when a lancing beam from its searchlight cut across the water, dazzling Mercer in its glare. He turned away, his focus on the canal, not caring that he’d abandoned his ruse of being a photographer.

Lauren and Vic were experienced divers who knew their limits. They wouldn’t push it this long if they didn’t think they’d make it back. Mercer had to stall. He had to give them a couple more minutes no matter what it cost. He reached for the towel, feeling the outline of the pistol inside.

Juan put his hand on Mercer’s wrist. The boatman had retrieved something from a compartment under the dash and showed it to Mercer. It was a laminated card written in Spanish. The dates had long since expired, but even Mercer understood that ten years ago Juan Aranjo had been a certified diver. Juan touched his watch, his eyes downcast. He shook his head. The simple finality of that gesture was like a spike thrust into Mercer’s chest. Lauren and Vic weren’t coming back.

Mercer looked toward the concrete lock again and saw a figure in a black wet suit climbing the ladder bolted to the seawall. The emotional swing from desolation to immeasurable joy was like a sledgehammer blow that left him dizzy. The person was slender, like Lauren, and about the right height. And then a second diver emerged from the water. It had to be Vic. He kept his weight off one leg as he lurched up the ladder.

Mercer had no idea what had happened but the relief was like a jolt of electricity that turned to dismay when a third figure climbed from the water.

Mercer pulled the camera to his eye, zooming in on the dark figures. He saw immediately that these were strangers. All three divers wore double tanks, not the single cylinders Lauren and Vic carried. The wet suits were different too. One of them pulled off his hood. His hair was jet black, and when he turned slightly, Mercer saw his features. The frogman was Chinese.

A fourth diver heaved himself up to join the other three. In his hand was an empty speargun. He, too, appeared injured.

Mercer let go of Lauren’s pistol and collapsed onto the deck. His legs could not support the burden his heart now carried. Juan eyed the distant divers then the motor launch. His decision was made for him. It was time to go.

He moved to the driver’s seat, flicked on the fuel pump, then fired the engine. He called across the water to the helmsman in the launch, explaining how his boat was temperamental. Before the pilot boat could get any closer, he engaged his craft’s drive and floored the throttle. The Pedro Miguel Lock quickly receded behind them.

Mercer noticed none of this as he fought the inescapable. Lauren was dead. From deep in his lungs and even deeper in his soul, the agonized roar exploded into the night, a shout that rippled across the water like the death cry of a mortally wounded animal.

Somehow Liu had known they were coming and was waiting with divers ready to intercept them. That was only possible if they’d been set up. Somebody close to Mercer had betrayed them to the Chinese, sold them out and let them walk into a trap.

Not somebody, he thought. He knew who had done it and even knew why.

The rage at Lauren’s murder became a burning flame, phosphorus white and agonizing. Mercer was consumed with finding Rene Bruneseau.